How to deal with passive perception?

[Scripten]

Hi everyone!

So, I've been running 5e campaigns for a couple of years now. They are fairly small, usually just one to three players, and mostly consist only of about three or four levels of content. Recently, however, I've started running a slightly larger party through a more consistent homebrew campaign. It's mainly just fluff, save for some modifications to spellcasting. Everything is going fairly well so far, except that I've been having to adjust to balancing for the larger group and for how experienced each player is, as the majority of them have been playing longer than I have.

My newest problem, though, has been tough to figure out. I've recently started using passive perception to avoid having each character make perception checks to spot hidden things. With six players, you basically never fail the check. If they are actively searching, then they can make the check. It's just the initial awareness is decided by passive perception. I like the system so far, but the party's WIS spread is not very wide, resulting in either two players passing most checks or everyone doing so.

So my question is: Does anyone have suggestions for making perception checks a little more dynamic and fun for the whole party? Some of my ideas so far have been adding non-perception skill proficiency to certain passive perception checks (to simulate perception of disparate environments and items in the surroundings) or just deciding separate DCs for different characters during active perception checks.

[RickAllison]

Passive Perception is an aggregate check done over several rounds. They are not specifically looking for something over that time (that would be actively rolling or taking 20), but keeping a weather eye out and taking the average of what they might get on any given round. It is for catching things that are visible over several rounds, like traps or someone in ambush. That object darting by in the corner of your vision? You either saw it or you did not and it would be a roll. That drop of saliva from the giant mouth on the roof that fell into a pool? If you didn't catch it when it fell, you don't have anything to meaningfully see.

[Tanarii]

There is no requirement to use passive perception to allow players to spot hidden things.

You're supposed to use it to allow characters that can spot hidden threats (ie are in an appropriate rank in the marching order) to do so, and are actively doing so (ie not doing something else, Per the adventuring chapter). And hiding creatures make stealth checks against hidden perception. But Pcs don't necessarily get to automatically use Passive perception to detect hidden things, without declaring they are looking for hidden things.

Certainly if you chose to allow it to avoid players constantly saying 'I search' and then rolling every round, that makes sense, and what passive perception is for. But you're within your rights to rule they must specify where they are searching first before they get to use passive perception, or ruling that only characters who have a reasonable chance of being able to see (ie marching order again) get to spot something hidden using passive perception.

Also don't forget anyone searching for something hidden somewhere isn't going to be paying attention for threats outside of that area. So they'll lose passive perception (doing another task, per adventuring chapter) for noting threats outside the area.

Basically if a bunch of people search an area, of course they have a better chance to find something that just a few. Allow it, it's the way things go. But take into account they don't have anyone on guard duty. :)

Edit: you also seem to be making a classic 5e error, which is assuming 'passive check' means passive on the part of the PC, and 'active check' means actively on the part of the PC. While this is the case in some cases for perception specifically, as called out by the rules for those specific perception checks, this is not universally true. The general rule for Passive checks means passive on the part of the player, not the PC. The PC can be doing something actively and repeatedly (like searching) and it can still be a passive check.

[Scripten]

Thanks for the quick replies! The most common use of a perception check for my party is when they enter a new area or room in a dungeon. It used to be that they would all roll perception checks and ask me what they saw. My solution at first was to set DCs for each player and respond with details for those who succeeded. It worked well enough, but it did cause hiccups in pacing. My alternative was to try and reduce the number of people rolling at once.

I should probably have specified that temporal events are not much of a problem. If something happens, I can make a determination on who catches it, so we already avoid the downfalls of plain probability. :smallbiggrin: Rather, I would like a system for giving the players small hints, such as saying, "You notice that the ceiling is sagging in the center" or "There is a strip of cloth on a tree branch you just passed while traveling". Having everyone roll means that it's almost certain that at least someone will succeed (making the roll essentially redundant unless the DC is absurdly high, which colors player interpretation) while using passive perception (that is, the aggregate of their awareness while out adventuring) will put the focus on only two players for every check.

I have been finding the latter more accommodating for our party, but I fear that having the party reliant on two characters' perception scores at all times will introduce more drudgery over time, albeit at a slower pace than the original attempt.

EDIT: I should also add that when a character succeeds on a passive perception check, that is when I inform them that they should make a roll. (Essentially, the passive check is to inform them that they detected something. The roll is to determine how well they did so.)

[RumoCrytuf]

Hi everyone!

So, I've been running 5e campaigns for a couple of years now. They are fairly small, usually just one to three players, and mostly consist only of about three or four levels of content. Recently, however, I've started running a slightly larger party through a more consistent homebrew campaign. It's mainly just fluff, save for some modifications to spellcasting. Everything is going fairly well so far, except that I've been having to adjust to balancing for the larger group and for how experienced each player is, as the majority of them have been playing longer than I have.

My newest problem, though, has been tough to figure out. I've recently started using passive perception to avoid having each character make perception checks to spot hidden things. With six players, you basically never fail the check. If they are actively searching, then they can make the check. It's just the initial awareness is decided by passive perception. I like the system so far, but the party's WIS spread is not very wide, resulting in either two players passing most checks or everyone doing so.

So my question is: Does anyone have suggestions for making perception checks a little more dynamic and fun for the whole party? Some of my ideas so far have been adding non-perception skill proficiency to certain passive perception checks (to simulate perception of disparate environments and items in the surroundings) or just deciding separate DCs for different characters during active perception checks.

The way I look at it is "Are they actively searching?" If yes, then roll. If not, it's passive. Simple :D

[Tanarii]

Thanks for the quick replies! The most common use of a perception check for my party is when they enter a new area or room in a dungeon. It used to be that they would all roll perception checks and ask me what they saw. My solution at first was to set DCs for each player and respond with details for those who succeeded. It worked well enough, but it did cause hiccups in pacing. My alternative was to try and reduce the number of people rolling at once.Absolutely no reason you can't keep doing this. That's a totally valid use of checking out an area. (Also passive investigation, depending on how they're approaching the search mentally - looking around or deducing locations.) Just take into account that:
1) There's no reason that such a thing might not take time. You don't have to give them passive perception as 'I glance around', ie just passively perceiving, so to speak, for hidden items, instantaneously.
2) If you do give them passive perception for 'I glance around' instantaneous search, they may see things that aren't hidden, or clues that something might be hidden, or whatever. But not straight out spot hidden things.
3) Getting their passive perception to actually spot hidden things might take time to search, even if the search is purely visual and doesn't require moving from a spot. Or it might require going over and digging through a closet or desk or barrels (or whatever). Totally depends on the circumstances of the hidden thing.
4) They may not be paying attention for other threats while doing #3.

As to hints, if they are critical to the players making an informed decision ... don't gate them by a perception check. Just give them to the players when they are needed. That's my $.02 on that, anyway.

Edit: Also, there's no reason to use a passive followed by a rolled perception check unless additional checks are needed for some reason. Rolling is really only required if it's time critical (ie use the search action to find something this combat round by rolling a check) or after the initial search circumstances change on a failed check (ie searching causes a wall to drop in place behind you if you fail to search on the first attempt). If they have 10x the required time to search an area, they automatically succeed. If they have exactly the time required to search an area and are searching one area after another area, passive perception. If they can't know what the result of the check was, passive perception. etc etc.

[DanyBallon]

It may not be the best solution, but our group is currently testing an houserule, where anything that is active (looking for, listening to, searching, etc.) is an investigation check, while everything that would be passive (noticing a detail, spotting something, hearing a noise, etc.) is a passive perception check done by the DM. This lead to remove ambiguity between what's belong to perception and what should fall under investigation, as players know that if they are telling the DM what their character is doing, then it's an investigation check, otherwise it's covered by the DM. One of the drawback, is that players must consider both perception and investigation when creating their character.

[Vogonjeltz]

Hi everyone!

So, I've been running 5e campaigns for a couple of years now. They are fairly small, usually just one to three players, and mostly consist only of about three or four levels of content. Recently, however, I've started running a slightly larger party through a more consistent homebrew campaign. It's mainly just fluff, save for some modifications to spellcasting. Everything is going fairly well so far, except that I've been having to adjust to balancing for the larger group and for how experienced each player is, as the majority of them have been playing longer than I have.

My newest problem, though, has been tough to figure out. I've recently started using passive perception to avoid having each character make perception checks to spot hidden things. With six players, you basically never fail the check. If they are actively searching, then they can make the check. It's just the initial awareness is decided by passive perception. I like the system so far, but the party's WIS spread is not very wide, resulting in either two players passing most checks or everyone doing so.

So my question is: Does anyone have suggestions for making perception checks a little more dynamic and fun for the whole party? Some of my ideas so far have been adding non-perception skill proficiency to certain passive perception checks (to simulate perception of disparate environments and items in the surroundings) or just deciding separate DCs for different characters during active perception checks.

For clarity, if it's passive it's a score, if it's active it's a check.

Scores are used to notice threats and doors, and anything else hidden which the character might have a chance to notice without actively trying to.

If they're engaged in a search (an action) they get to roll, and that gives them a significantly better chance of success, since they'll have already applied their score.

The way that scores work, having more characters doesn't necessarily make it likely to notice a threat, not unless the additional characters have higher Wisdom and proficiency in perception where the others had none.

[Naanomi]

Someone in our group is playing a Rogue/Druid with a Passive Perception in the 30s, it is a great boon to the party

[sir_argo]

This has been a huge problem in our group. In my opinion, Passive Perception is broken. We just had a session in which most of the mobs we fought started off hidden. Passive Perception does not use a roll. Without ever rolling a die, we were "surprised" every time. Something is wrong with that mechanic. One oddity of not rolling dice is that suppose person A has a 14 Passive Perception and person B a 13. It is impossible for person A to be surprised and person B to not be. That makes no sense. The entire table, and I do mean every player, told the DM something isn't right. Our DM just asserted, that's the rule. Well, the rule is stupid. I think Passive Perception should just be removed. Roll the dice every time. If you're not actively searching, increase the DC. Maybe use a +5 to the DC if you're not actively searching. Haven't play-tested that yet. But what I can tell you is it looks like every player is going to take the Alert feat next chance we get.

[Tanarii]

and anything else hidden which the character might have a chance to notice without actively trying to.This is not required by the rules. Hidden things actually specify that they are a check, per the PHB sidebar on finding a hidden object. The DM can of course use the normal rules for passive checks: it's a secret check, or you're doing it repeatedly over time (ie searching a large area). Or they can declare it automatic if you spend sufficient time and it's possible at all, ie searching a specific area for ten times as long.


If they're engaged in a search (an action) they get to roll, and that gives them a significantly better chance of success, since they'll have already applied their score.
An active combat check using the search action is probably a roll, since it's done once. But actively searching can also be a passive check, if (as above) it's either a secret check, or being done over time (searching as you go along).

A few specific rules aside, passive perception works like any other check. Even most of the specific rules are easily interpreted as normal use of passive checks of an active thing the character is doing, ie actively looking for threats while exploring so long as they're not actively doing something else that would deny them their score. Edit: and of course many times perception checks are secret checks, so they absolutely should use the passive score.

[Scripten]

Wow, lots of useful information here. Going to try to respond as best I can.


It may not be the best solution, but our group is currently testing an houserule, where anything that is active (looking for, listening to, searching, etc.) is an investigation check, while everything that would be passive (noticing a detail, spotting something, hearing a noise, etc.) is a passive perception check done by the DM. This lead to remove ambiguity between what's belong to perception and what should fall under investigation, as players know that if they are telling the DM what their character is doing, then it's an investigation check, otherwise it's covered by the DM. One of the drawback, is that players must consider both perception and investigation when creating their character.

That makes a lot of sense. My current ruling has been making the distinction as follows: Perception is a check for if you notice something. Investigation is a check for if you find something. Generally, this means that perception checks are made in my group by me (the DM) calling on a number of players to make the check, while investigation checks are generally called in reaction to a player asking to look for something. (Exception being if a player is asking to have their character be aware of the environment, such as searching for traps specifically.)


For clarity, if it's passive it's a score, if it's active it's a check.

Scores are used to notice threats and doors, and anything else hidden which the character might have a chance to notice without actively trying to.

If they're engaged in a search (an action) they get to roll, and that gives them a significantly better chance of success, since they'll have already applied their score.

The way that scores work, having more characters doesn't necessarily make it likely to notice a threat, not unless the additional characters have higher Wisdom and proficiency in perception where the others had none.

Right, and I like that. What I'd like to change is the reliance on one or two players for every passive check, since the passive perception scores are organized as such:

1 player with a 16
1 player with a 14
3 players with a 12
1 player with an 11

I am wondering if applying specific modifiers based on other skills (like survival for wilderness perception or arcana for magical phenomena) might be a way to spread the passive perception love around a bit. I'm also open to other suggestions.


This is not required by the rules. Hidden things actually specify that they are a check, per the PHB sidebar on finding a hidden object. The DM can of course use the normal rules for passive checks: it's a secret check, or you're doing it repeatedly over time (ie searching a large area). Or they can declare it automatic if you spend sufficient time and it's possible at all, ie searching a specific area for ten times as long.

An active combat check using the search action is probably a roll, since it's done once. But actively searching can also be a passive check, if (as above) it's either a secret check, or being done over time (searching as you go along).

A few specific rules aside, passive perception works like any other check. Even most of the specific rules are easily interpreted as normal use of passive checks of an active thing the character is doing, ie actively looking for threats while exploring so long as they're not actively doing something else that would deny them their score. Edit: and of course many times perception checks are secret checks, so they absolutely should use the passive score.

This is very good information. Thanks!

To add onto what I've already said, I'm mostly looking for ways to preserve verisimilitude, since my party is generally pretty good about balancing fluff and crunch. Calling for a roll, even in a party that manages meta very well, does change the atmosphere of a room and it breaks immersion a little bit if the players fail the roll but gain no information for having made the check. (That is, the player gains information but the character does not, creating a slightly jarring separation.) Using passive perception to make the determination if anything at all is seen, then rolling to make the determination of level of detail seems to solve that. But like I said, it means that the two players with the highest scores are basically perception mules, which is something I try to avoid for such general skills.

It's fine if the party rogue is the one who always picks locks and if the druid does all the tracking, but having the druid and cleric be the only ones to ever notice things and make rolls is less fun, IMO, because perception is such a universally applied skill.

[Tanarii]

But like I said, it means that the two players with the highest scores are basically perception mules, which is something I try to avoid for such general skills.If those two players are searching a room/area, then they aren't keeping guard for threats creeping up on them.

[Hudsonian]

It seems to me that passive perception is meant to be akin to the elvish "spot" ability in D&D Online where they get a notification that there is a secret nearby depending on there passive range. So I generally don't use passive perception on silly things like "what does the room look like" and if my players want to roll unpromted perception checks then they are welcome to, but it is likely that they find nothing even with a nat 20. I like to give away information without a roll if it is something that is important to completing a quest etc. But I like to give my rogue some love when it comes to noticing the secret passage that can go around the trap series in the hall, or the sewer grate that has wisps of conversation coming through it.

However, that is balanced by the wizard sometimes feeling when it is walking into a room that has high magic in affect. Or the monk noticing religious iconogrophy/martial techniques. The druid noticing when a plant is out of it's element or larger/smaller than it should be.

How I manage this is I set a notice number for elements around my campaign tied to a certain skill, if the PC meets that number in in that skill, they may roll the check. I've decided to subtract 10 from my notice numbers such that the passive is simply equal to their skill modifier.

[Scripten]

If those two players are searching a room/area, then they aren't keeping guard for threats creeping up on them.

That's true. I suppose it's at least one solution to it.


It seems to me that passive perception is meant to be akin to the elvish "spot" ability in D&D Online where they get a notification that there is a secret nearby depending on there passive range. So I generally don't use passive perception on silly things like "what does the room look like" and if my players want to roll unpromted perception checks then they are welcome to, but it is likely that they find nothing even with a nat 20. I like to give away information without a roll if it is something that is important to completing a quest etc. But I like to give my rogue some love when it comes to noticing the secret passage that can go around the trap series in the hall, or the sewer grate that has wisps of conversation coming through it.

However, that is balanced by the wizard sometimes feeling when it is walking into a room that has high magic in affect. Or the monk noticing religious iconogrophy/martial techniques. The druid noticing when a plant is out of it's element or larger/smaller than it should be.

How I manage this is I set a notice number for elements around my campaign tied to a certain skill, if the PC meets that number in in that skill, they may roll the check. I've decided to subtract 10 from my notice numbers such that the passive is simply equal to their skill modifier.

This was what I was thinking of trying out. Do you find that it works well in your games?

[Vogonjeltz]

This is not required by the rules. Hidden things actually specify that they are a check, per the PHB sidebar on finding a hidden object. The DM can of course use the normal rules for passive checks: it's a secret check, or you're doing it repeatedly over time (ie searching a large area). Or they can declare it automatic if you spend sufficient time and it's possible at all, ie searching a specific area for ten times as long.

I acknowledge that the sidebar describes how to adjudicate a search action.

However, Secret Doors (DMG 103), and Traps (DMG 121), can be noticed without trying, and also through actively looking, per the DMG. So they use the score prior to activating the search action.


An active combat check using the search action is probably a roll, since it's done once. But actively searching can also be a passive check, if (as above) it's either a secret check, or being done over time (searching as you go along).

A few specific rules aside, passive perception works like any other check. Even most of the specific rules are easily interpreted as normal use of passive checks of an active thing the character is doing, ie actively looking for threats while exploring so long as they're not actively doing something else that would deny them their score. Edit: and of course many times perception checks are secret checks, so they absolutely should use the passive score.

Search action does not use the score. Score gets used automatically by the DM outside the awareness of the players. When players choose to search, they do a check, but by that time the DM should already have compared the score unless the character was otherwise distracted (per traveling rules, noticing hidden creatures, and trap rules, for example).


Right, and I like that. What I'd like to change is the reliance on one or two players for every passive check, since the passive perception scores are organized as such:

1 player with a 16
1 player with a 14
3 players with a 12
1 player with an 11

I am wondering if applying specific modifiers based on other skills (like survival for wilderness perception or arcana for magical phenomena) might be a way to spread the passive perception love around a bit. I'm also open to other suggestions.

Well, you have a couple of tools I'd think.

First, not everyone is going to be eligible to notice something at all times in all places.

i.e. What is their travel order? Who enters the room first? (Maybe if there's a trap it would have been noticed by player #1, but they weren't first on the scene).

Second, just because you perceive something doesn't necessarily mean you understand its import.

I think you're on the right track with the other skills. Seeing something doesn't mean you recognize it as a hazard such unless you pass an Intelligence (Nature) check in the case of Wilderness hazards. Or seeing a magical plant beast you might not recognize it without a successful Nature check. Examples in the DMG include: Recognizing a patch of slime or mold that resembles something benign is an Intelligence (Nature) check, and wilderness hazards (DMG 105 and 110).

Maybe they see carvings on the walls, but without the requisite success at Intelligence (Arcana) don't recognize what they mean, or even that they are runes/glyphs.

Conversely, there could be a number of murals that tell a story recognized through Intelligence (History) or Intelligence (Religion) providing a parable that a Wisdom (Insight) check would recognize as delineating the existence of a lethal trap (which might also be found through Intelligence (Investigation) or signs of which might be visible from Wisdom (Perception).

So, next time your players explore a room (or a series of areas, if they split up to look around say, a very large room) compartment who is doing what, and you'll get more effect and possible granularity.

One thing you might also do: Write down the modifier totals for every character so you can figure out who is likely to pass:

Intelligence checks (History, Arcana, Nature, Investigation, Religion) and Wisdom checks (Perception, Insight, Medicine, Survival)

It may be that characters with higher stats skipped out on proficiency, and are actually less capable than those of middling stats, but with proficiency.

[mephnick]

It won't completely solve your problem, but one thing I do to combat how static PP ends up being is I don't set DC's for hidden objects (traps, doors etc). Instead I set "Hidden" modifiers and then roll a d20 against passive perception. So I decide something would be pretty hard to find, I give it a +5 modifier and take the next number on my pre-rolled list (which every DM should have) and that sets the DC to beat perception/investigation. So the next number is a 12, so that door in the room now needs a 17 perception to detect. It won't prevent a perception monster PC from detecting everything, but it grants enough variability that it's not the same every time and reduces my urge to meta-game DC's based on my party's passive perception.

It's basically giving objects a stealth score, really.

[Scripten]

Well, you have a couple of tools I'd think.

First, not everyone is going to be eligible to notice something at all times in all places.

i.e. What is their travel order? Who enters the room first? (Maybe if there's a trap it would have been noticed by player #1, but they weren't first on the scene).


That's true. The other notable fact is that the druid and the cleric (our high-perception guys) are also both pretty tank-y and therefore lead the marching order. I've had some fun with sneaking Giant Octopuses and the like behind them to grab the party wizard, but there's only so many times I can pull that off without becoming a jerk DM. (I will admit that I am highly amused that three of the six players roleplay terror at their respective near-death experiences, though.)

However, most of the time those two show up on scene first, meaning that if traps are going to be seen, they will see them.


Second, just because you perceive something doesn't necessarily mean you understand its import.

I think you're on the right track with the other skills. Seeing something doesn't mean you recognize it as a hazard such unless you pass an Intelligence (Nature) check in the case of Wilderness hazards. Or seeing a magical plant beast you might not recognize it without a successful Nature check. Examples in the DMG include: Recognizing a patch of slime or mold that resembles something benign is an Intelligence (Nature) check, and wilderness hazards (DMG 105 and 110).

Maybe they see carvings on the walls, but without the requisite success at Intelligence (Arcana) don't recognize what they mean, or even that they are runes/glyphs.

Conversely, there could be a number of murals that tell a story recognized through Intelligence (History) or Intelligence (Religion) providing a parable that a Wisdom (Insight) check would recognize as delineating the existence of a lethal trap (which might also be found through Intelligence (Investigation) or signs of which might be visible from Wisdom (Perception).

So, next time your players explore a room (or a series of areas, if they split up to look around say, a very large room) compartment who is doing what, and you'll get more effect and possible granularity.


Good points. I tend to run things this way as it stands.

My thought is that I might move some of the active rolls into passive checks. For example, having the rogue be more aware of how shadows are supposed to look from experience, as opposed to the Black Pudding they are about to step into. I just don't want to become so liberal with the perception rules that it becomes arbitrary.



One thing you might also do: Write down the modifier totals for every character so you can figure out who is likely to pass:

Intelligence checks (History, Arcana, Nature, Investigation, Religion) and Wisdom checks (Perception, Insight, Medicine, Survival)

It may be that characters with higher stats skipped out on proficiency, and are actually less capable than those of middling stats, but with proficiency.

This is a really smart idea. I'll definitely employ it come next session. Thanks!


It won't completely solve your problem, but one thing I do to combat how static PP ends up being is I don't set DC's for hidden objects (traps, doors etc). Instead I set "Hidden" modifiers and then roll a d20 against passive perception. So I decide something would be pretty hard to find, I give it a +5 modifier and take the next number on my pre-rolled list (which every DM should have) and that sets the DC to beat perception/investigation. So the next number is a 12, so that door in the room now needs a 17 perception to detect. It won't prevent a perception monster PC from detecting everything, but it grants enough variability that it's not the same every time and reduces my urge to meta-game DC's based on my party's passive perception.

It's basically giving objects a stealth score, really.

So instead of setting a DC and having the passive perception scores act as rolls against that DC, making the scores themselves a DC for me to roll against? Interesting! I like this and will try it out as well.

[Sir cryosin]

Use passive perception as they walk in and they can see and feel that something's not right with the room. But to figure out what's wrong with the room they had to do a investigation roll. Used perception to paint a broad picture and then use investigation for the smaller details. Party walking through a forest.
DM: looks at party's passive perception. He/she sees that player1 passive perception is high enough to that some movement catch his eye.
DM: tell player that he see some movement. Then he ask player1. To roll perception check.
Player1: rolls 20
DM: DC was 15. Ok you you see five large silhouettes coming from the right.
Player1: what are they and what to they look like?
DM: roll investigation.
Player1: rolls 14
DM: DC 10. You see large humanoids with green skin carry assortment of weapons. Wearing leathers and other hide armor. You would think these are orc.

If there are other orc like a shaman you would add more information to hit at there is a shaman with them.

[Tanarii]

Yeah I do something similar, example for illustrative purposes:
1) Cleric and Fighter are in the lead rank, both with high Wisdom (Perception).
2) Passive Perception exceeds DC to notice threat for front rank, Me: "The tracks in the dust in the passageway ahead all suddenly stick to the right side of the passage"
3) Rogue with decent Intelligence (Investigation) moves up and deduces location of traps in the (fairly obvious now) spot, and then uses Dexterity (Thieves tools) to disable it.

Of course, the point of the trap from a meta perspective isn't to catch the party, but rather to delay them and slow them down, creating more wandering monster checks. And of course, if they elect to bypass by sticking to the right side of the passage, and forget about it while beating a hasty retreat, there's a good chance the character leading the retreat won't have sufficient Passive Perception, especially with -5 for disadvantage, to spot the trap again. (Although when this has actually happened IMC (more than once) I always give the PC an Intelligence check to recall what the player has clearly forgotten, since that's exactly one what Int checks are intended for IMO.)

[Sabeta]

I assume the following of my players:
They have access to their five senses, and are capable and willing to use them constantly. Ergo, Passive Perception is always on, even while sleeping (but with a penalty)

Passive Perception is disabled if my players focus on a task not related to looking around: Ie, reading, cartography, etc.

Passive perception does not mean they're actively looking for anything, it's what they passively record about the world around them. Anything more is an active check.

Ie: A hidden object is probably unfindable without an active search. (Rare gems inside a specific crate, key under a rock, knife under a pillow.)

An easily missed object is findable with passive perception, and therefore PP is treated as a minimum score. (Ring in a pile of leaves, etched pebble dropped in mud, a specific person in a crowd)

A hidden or easily missed creature is findable by passive perception, compared against the creatures stealth roll. (Puppy hiding under the bed, ninjas hiding in the trees, treant hiding in a forest)

I'm fairly certain that this holds up to RAW, but if it doesn't oh well. My players have been content with this and never complain about not finding things they should have.

[Tanarii]

Passive perception does not mean they're actively looking for anything, it's what they passively record about the world around them.To me, this is a case of actively looking. They are actively looking at the world around them, over and over again, which is the very definition of what a passive check is used for.

OTOH if they are NOT actively looking at the world around them, or a specific area of it, or can't see part of it, then they don't get passive perception, because they are not actively interacting with the world (or some part of it). This is consistent with the rules for noticing threats and other activities.

In other words, there's no real difference to me between Passive Perception and any other passive skill.
0) Not actively using or cannot actively use = no check or score
1) Active use over and over again = passive score
2) Active use but DM needs to make check secretly = passive score
3) Active use but have x10 normal time and failure doesn't change results = automatic success if success is possible
4) Active use but you only have one chance and it's not secret and it's not an action done repeatedly

Examples:
0) Drawing a map while exploring a dungeon ; in the second rank of marching order cannot see past the person in front.
1) Front rank of marching order, keeping your eyes peeled for non-hidden threats, e.g. DM determined fixed DC to spot a patrol coming down the corridors towards them
2) Front rank of marching order, looking for hidden threats (ie trap DC, secret door DC, stealthy enemy rolled check)
3) Searching a room for 10 minutes (or whatever x10 times the time it would take to check it out is)
4) Combat Search Action to find something you know is there but cannot see

Perception is almost always Passive Perception score because it's really rare with perception that all of the following are true:
- Actively using (ie not doing something else)
- you only get one chance not multiple against the same person, place or thing
- it's not a secret roll
- it's not an action being done repeatedly

Basically, those only hold true in a Combat Search action to find a creature you know is there somewhere (doesn't need to be secret), and you need a result this specific round.

Edit: This is why it's important to remember that Passive Check does NOT mean passive on the part of the character. It means passive on the part of the player. There are some situations where the text for Perception checks happen to align with passive on the part of the PC = a Passive Perception score use, even though as I've explained above it's not necessarily correct for the Devs to have written that as 'passive' on the part of the PC in the first place. But passive PC = Passive Score & active PC = Active Check is absolutely NOT globally true, even for Perception checks.

[Maxilian]

Someone in our group is playing a Rogue/Druid with a Passive Perception in the 30s, it is a great boon to the party

How? Or does the double prof thing apply to passive perception too?

[Naanomi]

How? Or does the double prof thing apply to passive perception too?
Yes, all static bonuses apply... Expertise: Perception, consistent Advantage (via wildshape senses), Observant Feat, 20 Wisdom... only 'variable' influences don't make their mark (like Guidance) no matter how consistently applied