Using dice to track consumables (like ammo)

[Greywander]

I don't remember where I heard about a mechanic like this, but I just remembered it and thought some of you might find it useful. I think it might have been part of some cinematic rules for gunfights from another system.

Basically, tracking things like individual arrows can be a pretty substantial bookkeeping task. Some people don't mind (I generally don't), but others just can't be bothered and prefer not to track it at all. So instead of tracking arrows or other consumables exactly, we're going to track a rough estimate using dice.

Here's a simple version of how it works: When you use a certain consumable, roll a d6. If you roll a 1, then that means you just used your last one and now you're out.

Of course, it would be awkward if you just stocked up on something, e.g. bought a full quiver of arrows, then rolled a 1 straight away. So a more complex version is to start with a larger die, say, a d12, and every time you roll a 1, the die decreases in size by one step. Once the die reaches a certain size, say, a d4, then the next time you roll a 1 means you're empty. This helps guaranty that a full quiver will last a few shots, even if you roll nothing but 1s. It also helps communicate with the player when they're "full" (d12), or "running low" (d6), or "almost out" (d4).

This is a bit simpler to track than individual arrows or whatever other consumable you're tracking. It also helps that you can use a physical die to keep track of it, instead of having to write it on your sheet. This is also a bit more "cinematic", where your quivers might last a little longer than they're supposed to, or run out unexpectedly at a bad time. It can also create tension if you're running low and don't know exactly how many more shots you'll have. It's not for everyone; some people will still prefer to track things exactly, and some will prefer not to track things at all, and this kind of "fuzzy" tracking probably doesn't suit a campaign style where tracking consumables it important (e.g. a survival campaign where you need to track things like food exactly). What this does, though, it provide a nice middle ground that might appeal to those who currently don't track things and help speed up the tracking of those who already do.

I'm curious what the math is to make a quiver last for 20 shots on average. What die size do you start and end with? Should rolling higher than a 1 (e.g. a 2 or 3) also downgrade the die size? There's probably some formula that has the answers to these questions, but probability isn't my forte.

[Man_Over_Game]

I'm curious what the math is to make a quiver last for 20 shots on average. What die size do you start and end with?

Actually, I think that one's rather simple. You have a 1/4 chance to roll a 1 on a 4, so...4 rolls of a 1d4. You have a 1/6 chance of a 1 on a 6, so...you get the idea.

So I'd start with a 1d8, or a 1d10 if you want to account in the player's favor for the sake of RNG (which is always against the players).

[Sigreid]

Since there's no fumble in the game, why not on a natural one on the D20 attack roll you're out of ammo?

[aimlessPolymath]

I'm honestly not sure that it's better than straight ammo tracking for things you often spend (i.e. arrows, rather than potions)- you might be rolling this die multiple times per turn at later levels, which seems cumbersome compared to regular calculations. If someone like tracking arrows, I don't think this helps.

For potions, I'd be more OK with it.

Statistically, each die would last for a number of 'uses' equal to its size (1 in 6 to roll a 1 for a d6= 6 uses) before downgrading.
1d4: 4 uses
1d6: 10 uses
1d8: 18 uses.
1d10: 28 uses.

[Man_Over_Game]

Since there's no fumble in the game, why not on a natural one on the D20 attack roll you're out of ammo?

Statistically, that'd make sense.

Realistically, you'd run into situations where they'd run out of ammo immediately after leaving town.

[Greywander]

Since there's no fumble in the game, why not on a natural one on the D20 attack roll you're out of ammo?
First, because it sucks to just suddenly run out of ammo for no reason. With the die downgrading system, you get a gradual warning as you're approaching empty, while still not knowing exactly when it will hit. Second, because you could have just refilled your quiver, and then you're out after one shot? Again, the die downgrading system insures you get at least a few shots, even if you roll straight 1s, which is much more unlikely than just rolling a single 1. Third, because rolling a 1 on an attack roll already has an effect: it's an automatic miss.


Actually, I think that one's rather simple. You have a 1/4 chance to roll a 1 on a 4, so...4 rolls of a 1d4. You have a 1/6 chance of a 1 on a 6, so...you get the idea.

So I'd start with a 1d8, or a 1d10 if you want to account in the player's favor for the sake of RNG (which is always against the players).

I'm honestly not sure that it's better than straight ammo tracking for things you often spend (i.e. arrows, rather than potions)- you might be rolling this die multiple times per turn at later levels, which seems cumbersome compared to regular calculations. If someone like tracking arrows, I don't think this helps.

For potions, I'd be more OK with it.

Statistically, each die would last for a number of 'uses' equal to its size (1 in 6 to roll a 1 for a d6= 6 uses) before downgrading.
1d4: 4 uses
1d6: 10 uses
1d8: 18 uses.
1d10: 28 uses.
Wow, I didn't think it would be that simple. That's actually really easy to grasp. So if we go from a d12 to a d4, that's an average of 40 uses. We could just double the size (and price, and weight) of quivers or something. A "potion satchel" could be an interesting item, containing an indeterminate number of potions that use this die mechanic to track how many are left. Healing kits could also use this mechanic.

I'm surprised we haven't seen this used in a class mechanic, instead of tracking e.g. ki or sorcery points or a Lay on Hands pool. Heck, you could even use it as a spellcasting system. Maybe the level of spell you cast is the number you have to roll less than or equal to in order to downgrade your die, so casting a higher level spell increases how quickly you run out.

[Man_Over_Game]

First, because it sucks to just suddenly run out of ammo for no reason. With the die downgrading system, you get a gradual warning as you're approaching empty, while still not knowing exactly when it will hit. Second, because you could have just refilled your quiver, and then you're out after one shot? Again, the die downgrading system insures you get at least a few shots, even if you roll straight 1s, which is much more unlikely than just rolling a single 1. Third, because rolling a 1 on an attack roll already has an effect: it's an automatic miss.



Wow, I didn't think it would be that simple. That's actually really easy to grasp. So if we go from a d12 to a d4, that's an average of 40 uses. We could just double the size (and price, and weight) of quivers or something. A "potion satchel" could be an interesting item, containing an indeterminate number of potions that use this die mechanic to track how many are left. Healing kits could also use this mechanic.

I'm surprised we haven't seen this used in a class mechanic, instead of tracking e.g. ki or sorcery points or a Lay on Hands pool. Heck, you could even use it as a spellcasting system. Maybe the level of spell you cast is the number you have to roll less than or equal to in order to downgrade your die, so casting a higher level spell increases how quickly you run out.

Lol, that's basically what Psionic Dice were in the UA for the Psi Warrior and Soulknife: A die that scaled down whenever you maxed out a roll (instead of scaling down on a crit fail).

I'm not really sure why people didn't like it as a mechanic. I think it was a terrible idea for psionics (considering the one thing people can agree on with psionics is a sense of great control, not really reflected through an RNG resource), but that same thing could have easily been modified for some kind of fluctuating power from a curse or ailment or something. I hope they don't confuse that it was unwanted for where it was used, not how it did its job.

[Mjolnirbear]

This exact mechanic is also in Darkest Dungeons by Giffyglyph, although I think he got it from a different game originally.

It tracks all sorts of ammo and yes, also potions (called flasks)

[Foolwise]

If you are trying to avoid tracking things on the sheet, lowering the die size is not the solution to the stated problem. Some players may only use ranged weapons situationally and can go multiple sessions without firing an arrow/dart/dagger. If they dont track it, expect to hear What die was I rolling last? alot.

Sigreid's earlier suggestion of treating natural 1s on attack rolls using ammo is probably the simplest and most elegant solution to the stated problem. But I would modify it to the player is down to their last piece of ammo after rolling the 1. Nobody wants to miss with their last shot everytime.

As for situations where a player rolls a 1 immediately after restocking? Great roleplay opportunities. Did the small hamlet's shopkeep swindle the player? Perhaps an investigation check finds the quiver had a small hole gnawed out from some field mice.

The best tables embrace the fumbles.

[PhoenixPhyre]

How about this--use a d6

Instead of rolling it after every shot, roll it after every fight. If you roll a 1, you've expended that quiver entirely after picking up what arrows you can. Basically only tracking at the quiver level (instead of the shot-by-shot level) and allowing for variance in how many arrows you recover to "fill in the gaps".

[Townopolis]

How about this--use a d6

Instead of rolling it after every shot, roll it after every fight. If you roll a 1, you've expended that quiver entirely after picking up what arrows you can. Basically only tracking at the quiver level (instead of the shot-by-shot level) and allowing for variance in how many arrows you recover to "fill in the gaps".

Given the levels of abstraction D&D uses, and that most TTRPGs require to work, this is the idea that I think has the most potential.

[JonBeowulf]

I've heard folks gripe about tracking consumables and I've never understood the problem.

Use a thing and make a mark on your char sheet or your notes (even if online). When you're done with the encounter (or whatever), simply count the marks and do a tiny bit of arithmetic.

[Greywander]

I've heard folks gripe about tracking consumables and I've never understood the problem.

Use a thing and make a mark on your char sheet or your notes (even if online). When you're done with the encounter (or whatever), simply count the marks and do a tiny bit of arithmetic.
I don't mind it myself, but I know some people do. But even if you're fine with tracking them precisely, this is still different with it's own pros and cons. Not knowing exactly how much of something you have left allows for a bit of tension, when otherwise you could meticulously plan around what resources you do have. If you have, say, 3 rations, you know you can hike for 3 more days to reach a town. But if you're rolling that d4 every day to see if you've run out, it makes it a bit more exciting. For me, I kind of like boring and predictable, since I can plan around that. So, pros and cons, it depends what you're looking for or what you're trying to do. Both have a place.

[Lunali]

Wow, I didn't think it would be that simple. That's actually really easy to grasp. So if we go from a d12 to a d4, that's an average of 40 uses. We could just double the size (and price, and weight) of quivers or something. A "potion satchel" could be an interesting item, containing an indeterminate number of potions that use this die mechanic to track how many are left. Healing kits could also use this mechanic.

That's because it isn't that simple, a d4 is a bit better than 2 uses on average, d6 is a bit better than 3, d12 is slightly worse than 8 uses. (that's average number of rolls before you get a 1)

[Derpldorf]

uhhh... I just use a couple colored d20 for any ammunition and just flip 'em to the right number as I use them. Is there really a reason to roll anything?

[Mastikator]

I think keeping track of dice size is still book keeping. The only alternative to book keeping is not book keeping- IE don't keep track of arrows, don't roll. You either have the arrows item which gives you endless arrows (until the DM says you're out, or never!). You've transformed keeping track of numbers into a lottery system, whether that is an improvement is a matter of taste with no objective answer.

I know that if I was confronted with this I'd ask if I can just keep track of my arrows. And I know that if I had to do this, and inevitably rolled 1s and immediately ran out of arrows I'd feel miffed. PCs that rely on arrows tend to use hundreds of them, so either a) they keep looting arrows or b) they are allowed to buy hundreds of arrows or c) they don't have to keep track.

And here's why "they don't have to keep track" is a good option that should be given serious though: spell casters do not have to keep track of every single individual material component (unless it's expensive), and in those few games where they do they quickly realize why keeping track of that is bad: it's a big annoying waste of everyone's time and only serves to limit the fun of the players.

I've played in a game where I played as an archer who entered the party away from civilization, with no option to buy arrows and only my 20 arrows starter gear. So what happens? The DM forgot to put lootable arrows in his dungeon and I ran out of arrows. After a few sessions I run out of arrows and all I can do is defensive action (yes I could also use shortsword and get myself killed, which I did). And you know what? It totally sucked. (this is a human fighter, he does not have out of combat abilities)
The spell casters never had to worry about running out of material components though, so they never ran out of cantrips.
Lesson learned: if you let your players run out of ammunition then you're telling them they may as well not show up for the game.

[Cicciograna]

OP, the rules you are mentioning are from here:

https://intwischa.com/2011/05/house_rule_for_tracking_ammo/index.html

I remember that in the past I had written a little program to plot how many arrows one would, on average, fire when using different dice as starting dice. I have lost the program, though, so I don't have the results for the various dice, but I seem to remember that this was the distribution when using a d10:

https://i.imgur.com/vpWPKfv.png

Take this with a grain of salt, again, because while I am reasonably sure that the initial die was the d10 for this simulation, there is still the fact that I made this thing ~8-9 years ago and my memory is hazy.

[Lunali]

OP, the rules you are mentioning are from here:

https://intwischa.com/2011/05/house_rule_for_tracking_ammo/index.html

I remember that in the past I had written a little program to plot how many arrows one would, on average, fire when using different dice as starting dice. I have lost the program, though, so I don't have the results for the various dice, but I seem to remember that this was the distribution when using a d10:

https://i.imgur.com/vpWPKfv.png

Take this with a grain of salt, again, because while I am reasonably sure that the initial die was the d10 for this simulation, there is still the fact that I made this thing ~8-9 years ago and my memory is hazy.

It really bugs me that they did a fine job calculating the probability for retrieving arrows and completely ignored calculating the probabilities for the dice, assuming instead that you get an average of die size shots out of each die.

For the below calculations I'm confident in the number of rolls to get a 1, but not completely confident that probabilities don't change with the cascade.

d4 : 2.4
d6 : 3.8
d8 : 5.2
d10 : 6.6
d12 : 8
d20 : 13.5
d100:69

d4 : 2.4
d6 : 6.2
d8 : 11.4
d10 : 18
d12 : 26
d20 : 39.5
d100: 108.4

[JonBeowulf]

uhhh... I just use a couple colored d20 for any ammunition and just flip 'em to the right number as I use them. Is there really a reason to roll anything?

I was thinking the same thing, made even easier by using countdown dice (https://diceemporium.com/product/20-sided-30mm-countdown-dice/).

[Yakk]

Rolling an extra die is a waste.

And this eliminates the ability to say "I want lots of X".

So, start with inventory management system. You have a number of points equal to your strength score.

Light armor: 2
Medium armor: 4
Heavy armor: 6

Light weapons and most items: 1
Other 1 handed weapons: 2
Two-handed weapons: 3
Heavy weapons: 4

Having "insufficient storage" (not enough quivers or backpacks or whatever) costs 1.

Survival gear (tents, bedrolls, other non-consumables): 1 point provides a +1 bonus to survival checks. Every x3 provides an additional +1. (1:+1, 3:+2, 9:+3, 27:+4, 81:+5, etc). (This matters, as you might want to bring a pack mule to carry stuff here).

Basic consumables: 1. Includes ammo for your weapons, some water, some food, fire lighting stuff, etc.

Extra consumables: Per category.

When you roll a 1 on an attack roll, you are either out of ammo, or you lose a point of "extra consumables" for that type.

If you use up ammo in a fight, you can attempt to recover a used ammo point using a DC 15 survival check (every 5 you beat it you can recover an extra point, if you used more than 1).

For food/water, a failure means you run out of a it (unless you packed extra). A natural 1 means you lose 2 points (something went bad).

Large creatures and "heavy build" PCs get 2 points of inventory per strength instead of 1.

[Amechra]

This kind of rule is incredibly popular in the OSR community, though they usually use it at the quiver level. What's more, games that use it tend to use it for stuff like torches and rations as well.

So that's probably where you ran into it.

[Mellack]

I have tried this under the Darkest Dungeon rules and it worked, but it wasn't any simpler. I would rather just count manually. Having to roll an extra die and keep track of what die you were down to was easily as much tracking, and just added randomness IMO.

[dafrca]

I have tried this under the Darkest Dungeon rules and it worked, but it wasn't any simpler. I would rather just count manually. Having to roll an extra die and keep track of what die you were down to was easily as much tracking, and just added randomness IMO.

I agree, seems that you are just trading one SKU to track for another. But I could see where some would enjoy the RNG/Unknown limit element.

[Mjolnirbear]

I have tried this under the Darkest Dungeon rules and it worked, but it wasn't any simpler. I would rather just count manually. Having to roll an extra die and keep track of what die you were down to was easily as much tracking, and just added randomness IMO.

I *havent* but I considered it (among the many other houserule I've considered).

I really like the "natural one on a ranged attack roll means it's your last arrow" suggested above, but it wouldn't work for anything else: Rations (you don't use Rations with a die roll) or potions (you generally don't have 20 potions and don't roll a d20 with them anyways) for instance.

[Sigreid]

First, because it sucks to just suddenly run out of ammo for no reason. With the die downgrading system, you get a gradual warning as you're approaching empty, while still not knowing exactly when it will hit. Second, because you could have just refilled your quiver, and then you're out after one shot? Again, the die downgrading system insures you get at least a few shots, even if you roll straight 1s, which is much more unlikely than just rolling a single 1. Third, because rolling a 1 on an attack roll already has an effect: it's an automatic miss.



So you just decide to wave it for the first shot of 5. Or they tripped and spilled.

[Man_Over_Game]

All-in-all, I think it would be better to use this kind of mechanic for something that makes sense to be resolved using RNG.

For instance, using a system like this for consumable magic items that have a number of charges. Situations where either the player doesn't know what the actual quantity is for some reason, or it's an inherently fluctuating value to begin with (like channeling from a chaotic energy source or something).

What it does right is add predictability to something that normally is considered 'unreliable'. You can change the narrative from "It breaks 25% of the time" to "It has about 4 charges, but it can vary".

[heavyfuel]

I'm gonna go out on a limb and say that anyone who is lazy enough to not track ammo (someone like myself) is also lazy enough to not want to roll an extra die and keep track of which die they last rolled.

Imagine you play one week and end the session at a d8. Now it's two weeks later, are you gonna remember that it was a d8? Maybe. Maybe not. So you'll have to write it down at the end of the session, and then erase it when it goes up/down again. Is that really easier than making scores of 5 (either a square with a line through or 4 vertical lines with one through)?

What about tracking multiple ammo types? You now have to remember which ammo is using which die.

This is honestly more complicated than just keeping track.

Plus, it's my experience that whenever DMs start to enforce keeping score of ammo, players just say "Ok, I'll just buy 100 quivers and the Barbarian can carry 98 of them, and we'll always swap between combats" and just stop caring.

If you're ever playing on a world with very limited supply, then it's a different story, but I feel like for a the average D&D game, tracking ammo is a non-issue.

[Easy e]

This is a common method used in wargaming. It is a mechanic with a long and glorious track record.