Supply Die

[Kane0]

That's the point, if I want resource management, I want resource management.

Ah, right. That would mean this mechanic would not be for you then, which is OK! It was explicitly meant to remove that management, so there would be no way of twisting this to fit your preference. Much like the variant rules in the DMG, it was never intended to be universal.

Problem is, in your system, the ranger fires seven arrows in one encounter, then rolls a resource die, wham, one; and he's out of arrows. But why? How is that an advantage to have resource shortage that you cannot prepare for? Can't they just... bring more than seven arrows?

Okay, i'm thinking changing it so you don't lose the item on any roll of 1-2 but only a roll of 1-2 when you're down to a d4. That way a bigger die is a buffer before you start using up any equipment.
And you can bring more! Have someone else carry them, even if it's a pack mule or something.

For spellcasting. It's OK if you say "well you are out of bat guano and can't cast fireball", but it makes no sense the wizard might prepare fireball then find "oh I am out of bat guano" after an encounter. You'd think they would have known it when they prepare the spells... And if I were to play a fireball wizard, I'd make sure I bring enough bat guano to cast 20 fireballs or so.

The characters can't all be comically inept at preparing things.

Not the components for a single spell, *the entire component pouch*. But same as above you can absolutely bring backups, just not all on their person at the same time. Another good reason to have a familiar actually, and keep it alive.

Part of what i'm trying to simulate is the abstraction of wear & tear, spoilage, incidental damage and other things that would impact the gear you bring and use during adventures, and at the same time making the chance of them running out an actual danger rather than inconvenience, as that leads to tension and interesting decisions.

Alright, can't be all rant. Here are two suggestions from me:

• There's absolutely no point to use supply die for the first three or five days in the wild. Only start rolling them if you strayed from towns longer than that.
• Let characters bring their staple consumables. i.e., declare types of consumables they'll really bring a lot with them. Suddenly remembering you brought a random item such as a portrait or a grapple hook is one thing, suddenly forgetting to bring what defines you as a character at all is another thing. You can declare that rations are too heavy to be "staples".

Fair on both points. As above i'm thinking of changing to only losing stuff on the d4 roll, and to further incorporate the mechanic i've been adding in extra bits and pieces to feats, spells and class features to cover more bases. For example:
- Archery fighting style gives you a reroll for each Supply roll with ranged weapon ammunition
- Expertise with a tool gives you a reroll for each Supply roll with that tool
- Cantrips don't trigger Supply rolls, nor do levelled spells that use the phrase 'without expending a spell slot' (like spells from race, invocations, etc).
- Goodberry, create food/water, heroes feast and so on let you skip rolls for rations that day (but the caster would need to roll for their component pouch)
- Dungeon Delver increases your base Supply Die one size
- Lucky can be used to reroll a Supply Die roll (as can Inspiration)
- Healer gives you a reroll for each Supply roll with Healer's kits
- Magic Adept gives you a reroll for each Supply roll with Component Pouches

These are decent ideas. Alternatively, when supplies "run out" the player could decide which of her gear is no longer available.

Characters who are carrying fewer items than their capacity could even have empty slots to sacrifice to the Supply Die for this purpose, representing that our wizard, who knows she's going to need a lot of guano, has elected not to bring torches in the first place so she can just fill her pack with spell components. This would also solve my earlier problem, that running out of one thing somehow makes you more likely to run out of another.

Sounds good, but i'd go with one or the other and not both.