Action Points: Deep or Dumb?

[HumanFighter]

Lately I have been experimenting with various rules mechanics as I create my own tabletop system (medieval fantasy, classless, xp point buy).
For combat, I was thinking of trying something different. Action Points, or AP, might be fine but I'm not so sure about it.
Basically, rather than having the usual array of actions (Like Standard, Minor, and Move) I was thinking of having each character get 5 AP per turn on average.
There's ways to get more AP, obviously, like Perks/Feats, the Haste Spell, magic rings, etc.
Your "standard action" stuff like swinging a sword, casting a spell, grabbing someone, pushing someone off a cliff, etc. would be 3 AP, leaving you 2 for other stuff.
Using items, like potions or stimpacks, would be 2 AP. Opening a door: 1 AP, swinging a heavier weapon would cost 4 AP instead of 3. But a dagger only costs 2 AP to swing.
Standing up from prone would cost 3 AP, but if you are really agile, it might cost less.
These are just some examples.
Not sure if movement should cost AP, or if that should be its own separate thing. If movement does cost AP, I was thinking you get to move about 10 feet per AP you spend on movement, for average characers. If u spend all your AP for that round on movement, you get to "sprint" and double your total movement speed.
I have test-played this somewhat, and I get to thinking, is this even necessary? Does the Action Point thing really help with gameplay, or does it just slow down the game, as it is another number to calculate? The AP system feels pretty cool to me, but I could see how there might be some annoyances.
So, I'm on the fence about it. Do I stick with the usual standard action, side action, move action thing like D&D does, or do I go with Action Points?
Have any of you experimented with such a system? And if so, how did it go? I'd really like to know, as a nonprofessional, just-for-fun system designer.

[warty goblin]

AP have a lot going for them, namely simplicity and legibility. Honestly I prefer them to the traditional move/standard action system for exactly those reasons, if you have 3 AP you get to do 3 AP worth of stuff, and while the exact amount of time an AP represents can and should remain fuzzy, each one clearly represents some amount of time. This isn't true for move/standard action systems, where usually you can move say 30 feet as a move action, and then attack. Or you spend your standard action moving, and get to go twice as far, which kinda indicates a standard action is about as long as a move action. But if you don't move, you don't get a second chance attack, except in the editions with full round actions where you might get three more attacks so is a standard action less time than a move action? And when the hell do bonus or swift actions happen? It's all just a mess. AP avoids that mess, I'd say moving to AP was the one good decision Pathfinder 2e made.

I would warn you away from giving out differing numbers of AP though, and certainly not on a permanent basis. Whatever a turn based game uses as action currency is the most powerful thing in the game, to the point where strategies that reliably generate more actions are generally gamebreaking. Just stick with the clean, interpetable everybody has 3 AP, and you will save yourself a world of difficulty. 5 AP also works, but is a bit less tidy than 3.

The one open question with AP is how to solve reactions, i.e. stuff that happens during somebody else's turn. You could simply give everybody like 2 reaction AP that can only be spent on set things like attacks of opportunity, or some other ability that allows that; but see through above caveats about gaining extra actions. The traditional approach is to let players bank AP, and some them on some triggered effect during someone else's turn. You do need to think about when exactly AP refreshes (at the end of the round? Beginning?) and whether a creature can spend AP before their turn happens.

[NichG]

Lately I have been experimenting with various rules mechanics as I create my own tabletop system (medieval fantasy, classless, xp point buy).
For combat, I was thinking of trying something different. Action Points, or AP, might be fine but I'm not so sure about it.
Basically, rather than having the usual array of actions (Like Standard, Minor, and Move) I was thinking of having each character get 5 AP per turn on average.
There's ways to get more AP, obviously, like Perks/Feats, the Haste Spell, magic rings, etc.
Your "standard action" stuff like swinging a sword, casting a spell, grabbing someone, pushing someone off a cliff, etc. would be 3 AP, leaving you 2 for other stuff.
Using items, like potions or stimpacks, would be 2 AP. Opening a door: 1 AP, swinging a heavier weapon would cost 4 AP instead of 3. But a dagger only costs 2 AP to swing.
Standing up from prone would cost 3 AP, but if you are really agile, it might cost less.
These are just some examples.
Not sure if movement should cost AP, or if that should be its own separate thing. If movement does cost AP, I was thinking you get to move about 10 feet per AP you spend on movement, for average characers. If u spend all your AP for that round on movement, you get to "sprint" and double your total movement speed.
I have test-played this somewhat, and I get to thinking, is this even necessary? Does the Action Point thing really help with gameplay, or does it just slow down the game, as it is another number to calculate? The AP system feels pretty cool to me, but I could see how there might be some annoyances.
So, I'm on the fence about it. Do I stick with the usual standard action, side action, move action thing like D&D does, or do I go with Action Points?
Have any of you experimented with such a system? And if so, how did it go? I'd really like to know, as a nonprofessional, just-for-fun system designer.

Last campaign I ran I used an AP system with basically a total rewrite of D&D, and it was pretty nice. It can be a little bit more book-keeping than people are used to, particularly with players remembering to use all their action points when it would work out to let them do a lot of stuff rather than just doing 'one thing' in a round, but its something that people can get used to.

The thing that made AP really nice in that system was in concert with a Tome of Battle style set of boosts and maneuvers and such, because you could have boosts cost a small number of AP but apply to all subsequent attacks in sequence (with certain maneuvers allowing boosts to be retained into the next round, other things acting like combo breakers, etc). Especially if you have mechanisms for storing AP from round to round, it can make sense to save up and then do a bunch of things that build on each-other rather than doing the same thing each round.

Basically the main thing is to be careful about things that scale AP, for the same reason as any action economy stuff is generally very potent. Rather than making attacks cost 3, it may make sense to set the numbers so that attacks cost 4 or even 5 so that you have enough granularity that for example a +1 or +2 from here or there isn't too big of a deal but it can still matter (especially if excess AP carries over from round to round), and charging +1 or +2 AP for adding extra effects to things isn't too bad either. One nice thing with AP is it opens up the design space for attacks that drain that unused AP from an enemy's reserve as a fairly low level easy bonus thing you can have - basically, it can't totally stun-lock an enemy since they will still generate AP on their round, but it can easily lock down abilities that an enemy can't pay for using only a single round of AP. You can also have stuff like status conditions where you take damage per AP spent to represent some kind of bleeding or 'tangled in thorns' thing, status conditions that reduce AP refresh, terrain that costs AP to move through...

Anyhow, this was the system I ended up making: https://drive.google.com/file/d/1-Jb-bbEfNNvFsKCroV1ONaJ4umTOTTQ_/view?usp=sharing

Campaign went from Lv3 to Lv18 or 19 iirc. Some stuff in there got silly by the end, but more because of the damage dice scaling of a couple of the Gadgeteer abilities that could be added to their basic attack than inherently because of the AP system. I had made spells tend to cost 1.5 to 2 attacks worth of AP to cast, and that wasn't generally worth it with the specific numbers in here, but I think that could be fixed relatively easily with a second pass over what's there.

[stack]

Pathfinder second edition gives three actions per round; some things cost two or three actions. Slowed and stunned mean you get less, quickened gets you one more (for a limited set of actions, doesn't stack). You also get one reaction for off-turn stuff.

[Yora]

The main problem with action points is the same problem as with potions. To a certain type, and apparently substential number of players, limited resources are something that "I need to save for more important situations later". I do that all the time. If it has limited uses, it automatically feels too important to use in any situation that isn't absolutel life and death.

I encountered an alternative mechanic for this a while back in Coriolis, where you can get a substential boost to almost any roll after you rolled it, at any time and as often as you want. There is no limit to the uses for the PCs, but any time you use it, you also enable the opposing NPCs to use it once. (Or the GM might cause some other complications with those NPC action points.)
This system provides a bonus similar to action points, but the players never have to hold on to them for later in case they might really need them.
(The whole game is also set up in a way that the bonus is huge and non-specialized characters might not be able to do many tasks without it, to increase the incentive to accept the bonus now and deal with it coming to you later.)

[stack]

The main problem with action points is the same problem as with potions. To a certain type, and apparently substential number of players, limited resources are something that "I need to save for more important situations later". I do that all the time. If it has limited uses, it automatically feels too important to use in any situation that isn't absolutel life and death.

I encountered an alternative mechanic for this a while back in Coriolis, where you can get a substential boost to almost any roll after you rolled it, at any time and as often as you want. There is no limit to the uses for the PCs, but any time you use it, you also enable the opposing NPCs to use it once. (Or the GM might cause some other complications with those NPC action points.)
This system provides a bonus similar to action points, but the players never have to hold on to them for later in case they might really need them.
(The whole game is also set up in a way that the bonus is huge and non-specialized characters might not be able to do many tasks without it, to increase the incentive to accept the bonus now and deal with it coming to you later.)

OP is talking about an action economy system, not a resource for bonuses. Different use of "action points".

[Yora]

How can I be able to still write so much when I'm not able to read.
Better call it a night.

(But Coriolis has thiae action points too.)

[HumanFighter]

AP have a lot going for them, namely simplicity and legibility. Honestly I prefer them to the traditional move/standard action system for exactly those reasons, if you have 3 AP you get to do 3 AP worth of stuff, and while the exact amount of time an AP represents can and should remain fuzzy, each one clearly represents some amount of time. This isn't true for move/standard action systems, where usually you can move say 30 feet as a move action, and then attack. Or you spend your standard action moving, and get to go twice as far, which kinda indicates a standard action is about as long as a move action. But if you don't move, you don't get a second chance attack, except in the editions with full round actions where you might get three more attacks so is a standard action less time than a move action? And when the hell do bonus or swift actions happen? It's all just a mess. AP avoids that mess, I'd say moving to AP was the one good decision Pathfinder 2e made.

I would warn you away from giving out differing numbers of AP though, and certainly not on a permanent basis. Whatever a turn based game uses as action currency is the most powerful thing in the game, to the point where strategies that reliably generate more actions are generally gamebreaking. Just stick with the clean, interpetable everybody has 3 AP, and you will save yourself a world of difficulty. 5 AP also works, but is a bit less tidy than 3.

The one open question with AP is how to solve reactions, i.e. stuff that happens during somebody else's turn. You could simply give everybody like 2 reaction AP that can only be spent on set things like attacks of opportunity, or some other ability that allows that; but see through above caveats about gaining extra actions. The traditional approach is to let players bank AP, and some them on some triggered effect during someone else's turn. You do need to think about when exactly AP refreshes (at the end of the round? Beginning?) and whether a creature can spend AP before their turn happens.

Yes, I was considering using 3 AP instead of 5 per round because it is a bit neater. However, I like 5 better because I feel it gives me more to work with when it comes to the different weapons and spells.


Pathfinder second edition gives three actions per round; some things cost two or three actions. Slowed and stunned mean you get less, quickened gets you one more (for a limited set of actions, doesn't stack). You also get one reaction for off-turn stuff.

I do like Pathfinder 2e's Action System. It's solid and good. Unlike D&D 5e's action system, which is not confusing or anything, just the wording is a bit weird (Action? Bonus Action? Why must they change the name of the Side Action in every edition? Lol)
---
Very interesting responses here, folks. And yeah, when it comes to my AP system, a character cannot save up his AP for another turn, unless they have a special ability related to the Tactics skill, which I feel makes sense. But generally, any unused AP goes to waste at end of turn. However, there is a Defensive Stance ability which allows one to convert any unused AP at end of turn into a Defense Bonus, making them harder to hit until their next turn begins.
And new AP is only generated by a character when their turn begins.

Based on these responses, I am now leaning a bit more towards having an AP system for my game. One thing I just realized is, when it comes to Boss Enemies soloing the party, in earlier editions of D&D the boss might get screwed because of the action economy being against them, since they are outnumbered. D&D 5th did fix this with the Legendary Actions, but I found these to be annoying, OP, and unfair, and kind of broke up the flow of the combat too much.

As far as reactions go, not sure what to do about that yet. All I know so far is, if a character gets Staggered (a lesser condition compared to Stunned) they get a -3 Defense Penalty, can't do reactions, such as parries and AoOs, and they get 1 less AP to work with when their next turn comes around. But, Staggered goes away immediately at the beginning of the Staggered person's next turn, unlike Stunned.

[NichG]

The way I handled reactions is that a character can borrow against next round's AP generation when using a reaction that only fires in response to a specific trigger (this was one sort of reactive ability), but for things where the character got to choose when to fire off the off-round action they had to have reserved AP in their pool from the previous round. So a character could for example have an ability that let them spend 2AP to take a 5ft movement on someone else's turn, but they'd have to reserve AP to do that. But if they had an ability that let them spend 5AP to reroll a failed saving throw, they could borrow against next round to pay that. It actually never came up that someone borrowed AP and then had something happen between then and the start of their round to make them generate less AP than they had borrowed, but I think I'd just say 'you got lucky' and move on there if it had happened.

The way I handled banking AP was to have it be based off of ability score modifiers (sum of Int and Wis modifiers, minimum pool equal to your per-round generation). If anything, I think this was too strict - I'd probably have it be like characters can bank 5 + modifiers if I did a rules update. Letting people bank AP (as long as they can't enter combat with AP pre-banked) is probably good for helping the system be more forgiving. Especially because one thing I've noticed is there is a certain kind of player who will be really bothered if they end up 'wasting' AP here or there. So letting it roll over helps them not try so hard to fit what they want to do exactly into their AP budget.

If you're worried about characters going nova by saving up a lot of AP and then taking multiple actions before someone can respond, you could have a rule that if someone spends more than X AP in sequence, their turn temporarily halts and they can pick it up again at initiative - 10, and that keeps going until everyone has spent their AP. I wouldn't make X low since it'd bog things down - most characters/enemies should not trigger this rule in usual play. But it'd be good for having the boss with 25AP not just unload a dozen attacks at once on one PC or something like that, or if you wanted to have spells that required a certain number of AP to be invested in them between start of casting and end of casting with all the interrupt/etc considerations in play.

[Vahnavoi]

This banking of action point has pretty much never come up in games I've played, due to some combination of the following:

- taking an action that costs more action points than what you have is permitted
- common actions, such as attacking or casting spells, take so many points that they're virtually always done on the last action point(s) (see above)
- passing within a round is allowed - f.ex., if you have first turn on round and can't think of what to do, you can wait until everyone else has either acted or passed.
- there's an usable "defend" action that consumes all action points and ends a turn.
- a new round begins and action points refresh only after everyone has spent all their points.

[olskool]

Lately I have been experimenting with various rules mechanics as I create my own tabletop system (medieval fantasy, classless, xp point buy).
For combat, I was thinking of trying something different. Action Points, or AP, might be fine but I'm not so sure about it.
Basically, rather than having the usual array of actions (Like Standard, Minor, and Move) I was thinking of having each character get 5 AP per turn on average.
There's ways to get more AP, obviously, like Perks/Feats, the Haste Spell, magic rings, etc.
Your "standard action" stuff like swinging a sword, casting a spell, grabbing someone, pushing someone off a cliff, etc. would be 3 AP, leaving you 2 for other stuff.
Using items, like potions or stimpacks, would be 2 AP. Opening a door: 1 AP, swinging a heavier weapon would cost 4 AP instead of 3. But a dagger only costs 2 AP to swing.
Standing up from prone would cost 3 AP, but if you are really agile, it might cost less.
These are just some examples.
Not sure if movement should cost AP, or if that should be its own separate thing. If movement does cost AP, I was thinking you get to move about 10 feet per AP you spend on movement, for average characers. If u spend all your AP for that round on movement, you get to "sprint" and double your total movement speed.
I have test-played this somewhat, and I get to thinking, is this even necessary? Does the Action Point thing really help with gameplay, or does it just slow down the game, as it is another number to calculate? The AP system feels pretty cool to me, but I could see how there might be some annoyances.
So, I'm on the fence about it. Do I stick with the usual standard action, side action, move action thing like D&D does, or do I go with Action Points?
Have any of you experimented with such a system? And if so, how did it go? I'd really like to know, as a nonprofessional, just-for-fun system designer.

Long before PATHFINDER II did it, I took the ACTIONS system from the MYTHRAS RPG and used them in D&D5e. They worked GREAT! Everyone gets 3 ACTIONS and 1 REACTION to use for physical Saves or Defense (I allow anyone to defend, increasing their AC by 1 for non-martials or by their proficiency bonus for martials) or reactions to other opponents' actions. In addition, the Action Surge Fighter ability (which I only give to the Champion subclass) and Rogue's Actions each give an added ACTION that they can use (see below). Certain FEATS will add ACTIONS under certain circumstances. Each ACTION represents ROUGHLY (and I do mean roughly) TWO SECONDS of activity.

These ACTIONS can be used for moving, crossing an obstacle or difficult to pass terrain (ie difficult terrain eats up two ACTIONS) or for making an attack. Making multiple Attacks is possible with each attack taking up 1 ACTION. When a PC gets multiple attacks, they may either attack multiple opponents in their frontal arc OR roll as many Damage Dice (plus adds) as the multiple Attacks which they possess against a single target. This is the PLAYER'S choice. So a Fighter with 3 attacks could attack three goblins for 1D8 each; two goblins for 2D8 and 1D8 respectively; or one goblin for 3D8 per ACTION. Yes, this means that Martials can do lots of damage but why not allow that? Look at what a Fireball spell can do!

Spellcasting takes 1 ACTION for Verbal components; 2 ACTIONS for Somatic & Verbal components; and 3 ACTIONS for Material, Somatic, & Verbal components. This is the price my players pay for the power of magic. The Combat Caster FEAT gives the PC one additional ACTION to be used but for spellcasting ONLY!

Now, here's where my ACTIONS system differs from PATHFINDER. Everyone takes their first ACTION... TOGETHER. Then everyone takes their second ACTION, yes you guessed it, TOGETHER. Finally, everyone takes their third ACTION... TOGETHER. Actions taken together are considered to be occurring simultaneously. Everyone resolves their ACTION in any old order and then the effects are applied. Please take note that under this system, two opponents could kill each other in the same ACTION. The Fighter's Action Surge and any FEAT acquired ACTIONS come at the END of these three "phases." The Rogue, however, may "insert" their ACTION into the 3-action sequence AT ANY TIME, including before the first ACTION cycle starts. These bonus ACTIONS are considered their own "phases" or "cycles" with regards to the effects which occur during them. Opportunity Attacks will eat up one's only REACTION and a REACTION can be used during ANY ACTION "cycle" or "phase." Various Conditions (Stunned, Knocked Down, Off Balance) will REDUCE the number of ACTIONS a PC or monster has available to them.

That's basically how I do my ACTIONS in a nutshell!

[Psyren]

There are a number of CRPGs that do AP well, if you're looking for an example to crib from. The most notable example that comes to mind is Divinity OS2. While it's not an RPG per se, XCOM has RPG elements like squad mates that level up and gain new abilities, and that one uses a fairly robust action point system as well.

The biggest negative of action points is that tracking them can be a pain relative to a much simpler/standardized action system, but assuming you clear that hurdle, action points give you a lot more granularity and additional levers to balance impactful combat actions like spells.

[LibraryOgre]

Hackmaster uses seconds, which works similarly. Swinging a sword requires X seconds between swings, depending on your skill and the type of sword. Casting a spell requires Y seconds, and mages have Y plus 5 seconds of spell fatigue afterwards (clerics don't have spell fatigue). Between a weapon's Xs (i.e. between 1X and 2X) you can do some other things, like move and make other defenses, but other actions will "reset the count", meaning if you do something on X+3 that resets the count, you then act on X+3+X, instead of 2X.

For example, if your initiative is 3, and you're using a dagger with a speed of 4 (due to your specialization dropping the speed), you'll get to start at 3; if someone is right next to you, you'll stab them on 3, then act again at 7 (3 initiative + 4 speed), then 11, 15, 19, etc. If you do something at 10 that resets your count, you'll act on 14 (10+4), then 18, 22, etc. If you kill the guy at 7, then have to walk 50' to get to the next guy, you'll act at 12 (since that's when you're close enough to use your dagger again)

[Easy e]

As a long time wargamer, I have a deep, abiding, and completely irrational hatred of Action Points.

I would like to tell you why they are a terrible idea, but my hatred is irrational; so I can not.

[warty goblin]

There are a number of CRPGs that do AP well, if you're looking for an example to crib from. The most notable example that comes to mind is Divinity OS2. While it's not an RPG per se, XCOM has RPG elements like squad mates that level up and gain new abilities, and that one uses a fairly robust action point system as well.


New XCOM doesn't use AP, it sort of uses the D&D system of a move and standard action, with the additional wrinkle that using your standard action generally prevents you from using the move action. This doesn't completely end your turn at least in XCOM 2 (can't remember 1 well enough), as there are free actions such as evacuating that can still be used after attacking.

These weird idiosyncratic rules about what action fills what slot, which actions can be taken after which other actions, and so on are exactly why I prefer a true AP system. XCOM often feels like I'm wrestling with the rules (not helped by the crappy interface). Gears Tactics, which just gives you 3 AP, has exactly zero of these issues, and plays much more fluidly and naturally as a result.


The biggest negative of action points is that tracking them can be a pain relative to a much simpler/standardized action system, but assuming you clear that hurdle, action points give you a lot more granularity and additional levers to balance impactful combat actions like spells.

I generally find AP really easy to track, because AP are a completely fungible resource. If I have X AP, I can do any set of stuff with total cost <= X. Since the number of AP in most systems is like 3 or 4, the arithmetic is trivial.

I do not have to worry about whether action A is a standard action and B is a minor and C is a move but D is full round and E is a standard action but gives me a triggered action F which uses the same slot as thing G which is enabled by A, and what slot did C take again? This is annoying, tedious, and feels a lot less like the system is enabling me and a lot more like I'm wrestling it into some sort of cooperation.

[NichG]

This banking of action point has pretty much never come up in games I've played, due to some combination of the following:

- taking an action that costs more action points is permitted
- common actions, such as attacking or casting spells, take so many points that they're virtually always done on the last action point(s) (see above)
- passing within a round is allowed - f.ex., if you have first turn on round and can't think of what to do, you can wait until everyone else has either acted or passed.
- there's an usable "defend" action that consumes all action points and ends a turn.
- a new round begins and action points refresh only after everyone has spent all their points.

Do you mean 'I have not played with banking AP' or 'even in systems I've played that allow banking AP, people don't do it' or 'even in systems that do not allow banking AP, I haven't seen players spend any time solving knapsack problems to try to land on exactly zero AP left each round'?

[Vahnavoi]

I mean in systems I have played, some combination of traits mentioned stops it from being a thing.

[Pauly]

A well done AP system is superior to any turn system. In effect a standard turn system is an AP system strictly regulating when and what you do. The main issue with AP systems is that some players find them more complex than regular turn systems.

In addition to the regular benefits of flexibility., Some additional features an AP system can include.
- You can save APs from turn to turn up to a limit. This can allow a character to take a lull, collect their breath, then have a very active turn. This gives you more cinematic gameplay.
- Allows for complex long tasks to take place over multiple turns.
- Improves granularity in spell casting as more powerful spells can cost more APs than simple spells. In D&D a 1st level spell and a 7th level spell both have the same cost to cast.
- As for spells, feats and other actions can be given more or fewer AP costs.
- It allows for APs to be spent in the enemy’s turn as reactions. Although this should come at a tax, say +50% cost, otherwise it becomes more efficient to spend your APs in the enemy’s turn.

I have found AP systems where you have the ability to generate and allocate extra APs the most fun. Space Hulk has a very good simple system for doing this.

The best RPG AP system I’ve played was a homebrew re-write of D&D. You received your CON/2 APs per turn. Iirc it was capped at 5 or 6 new APs per turn with a maximum of 9APs of carryover + new APs.
Damage was dealt directly to your CON, and as your CON dropped your character slowed down and needed more rests to have effective turns. It’s been a long time since I played the system, but I think you had a damage track of your HPs and lost 2 CON for every 1/6th of your HOs you lost.

[Quertus]

Action Points can, if done right, make for a fun minigame. The question is, do you want this to be a fun minigame? Is this where you want focus? “Yes” and “No” are both valid answers to this question.

Personally, I prefer AP systems with more like 7-12 AP to work with, allowing costs like:

Attack: 5 AP
Parry: 2 AP, from those set aside in Reaction Pool
Reflexive Parry: 4 AP from next turn
Bladesinger Strike & Parry: 4 AP (Attack, plus add a Parry to the Reaction Pool)
Hexblade Curse Strike: varies. Add the AP cost of the attack, plus half the AP cost of the Curse to determine the AP cost of this ability.
Chronomancer Shuffle: 2 AP. Add 1 AP to target character’s next turn.

Or

Elves: +1 AP, -1 Reaction Pool - although elves can act quickly, the long-lived race is slow to react to the unexpected.

Also, I’m a huge fan of things like “Power Word spells only cost 1 AP”; ie, the *power* of a spell is not tied 1-to-1 with its action point cost.


Hackmaster uses seconds, which works similarly. Swinging a sword requires X seconds between swings, depending on your skill and the type of sword. Casting a spell requires Y seconds, and mages have Y plus 5 seconds of spell fatigue afterwards (clerics don't have spell fatigue). Between a weapon's Xs (i.e. between 1X and 2X) you can do some other things, like move and make other defenses, but other actions will "reset the count", meaning if you do something on X+3 that resets the count, you then act on X+3+X, instead of 2X.

For example, if your initiative is 3, and you're using a dagger with a speed of 4 (due to your specialization dropping the speed), you'll get to start at 3; if someone is right next to you, you'll stab them on 3, then act again at 7 (3 initiative + 4 speed), then 11, 15, 19, etc. If you do something at 10 that resets your count, you'll act on 14 (10+4), then 18, 22, etc. If you kill the guy at 7, then have to walk 50' to get to the next guy, you'll act at 12 (since that's when you're close enough to use your dagger again)

Not sure if it’s common parlance or not, but I refer to such systems more generally as using “ticks”, whether those ticks are abstract or map to discrete units of time.

Now, I might get to feel really dumb for asking, but aren’t ticks and AP, like, opposites?

I mean, sure, there’s all kinds of what I call “unstructured” initiative models, from “bidding” to “take turns” (Battletech style) to “everyone goes at the same time”. But for structured, formulaic initiative models, there’s AFAIK two opposing schools of thought: turns, and ticks.

In “turns”, you get a “power bar”, a set of actions you are allowed to take, whether that’s “a Standard and a Move” or “5 action points”. Outside strange abilities that interact with this system (like “Hold an Action” or “Delay”), the choice of actions is independent of when the next turn occurs. Whereas, in ticks, what single action the character chooses to take determines how long until they get to act again.

[Leon]

They work well for the game that were designed to use them, retrofitting them to a game/system not designed for them seem a lot of work for not much gain.

[Asmotherion]

I like how this works, and thus PF2e is my favorite system so far.

[MoiMagnus]

Have any of you experimented with such a system? And if so, how did it go? I'd really like to know, as a nonprofessional, just-for-fun system designer.

The question of "action points VS actions" is very similar to "every ability using the same resource VS each ability having its own number of uses".

By allowing more flexibility you increase the depth of the game unless some choices are strictly better than others in which case the depth is reduced.

For example, by allowing to make more attacks if you don't move, you push players toward moving as little as possible, which lead to combats that are much more static. Sure, you might get some bonuses from flanking, but is it ever worth losing an attack to move around? Obviously, you can compensate for it, for example by having a lot of "special attacks" include a movement (charge or teleportation), or by making bonuses from good positioning strong enough for it to be worth the cost. But it's some significant work to do, while on the other hand systems in which the movement is "free" makes it much more affordable for players to move around even for small tactical advantages, leading to potentially more dynamic battles.

In general, the more flexibility you give to players, the more you have to make sure that the optimal playstyle is not a boring one that ignores half of the game.