DARK SUN veterans know that your food and water are often in short supply. A perilous journey across a trackless waste can be made even more dangerous if a sudden sandstorm destroys your food, or a sneaky pack of jozhals steals your waterskins while you're resting!
Tracking food and water individually for everyone in your party may be a little hard on the players, though. They want to have sword-and-sandal adventures, not adventures in accounting!
One way to sidestep this is to give all the accounting duties to one player who enjoys or tolerates that kind of paperwork, and let them track supplies for the whole party. This can still be awkward, though, if you need to figure out who's carrying what, or how much the half-giant is hauling around as compared to the low-strength magician. And it's still a lot of number-tracking.
If you want to abstract your food and water supplies to require far less accounting, here's a simple way to do it!
Set aside three six-sided dice for use as your supply dice.
Your entire party carries supplies as a group. Strong characters carry more; the team works as a whole to carry the food and drink that they need. Your level of supplies determines how many supply dice your party has, and also affects your encumbrance. Everyone in the party has a minimum level of encumbrance set by your supplies: If you're carrying a lot of supplies, everyone's heavily encumbered by them, whether they have armor and other heavy gear, or not. Your supplies are:
LEAN - 1 die - You have a small amount of dried food and a few skins of water each. Lean supplies cost 1 sp per person.
AMPLE - 2 dice - You have a good quantity of dried and preserved food, plus a little fresh food, and a good amount of water and maybe another beverage. Everyone in the party is at least lightly encumbered by your supplies. Ample supplies cost 5 sp per person.
BOUNTIFUL - 3 dice - You have a selection of various foodstuffs and snacks, plus plenty of water and a variety of other drinks. Everyone in the party is at least heavily encumbered by your supplies. Bountiful supplies cost 25 sp per person.
If your party wants to increase their current level of supplies, just pay the difference while you're in a place where you can purchase additional supplies. If you want to decrease your level of supplies (perhaps so that you can travel more rapidly), just discard some of the excess food and water!
If your party splits up, you choose how to split the supply dice between the various groups. If you don't allocate any dice to one of the sub-groups, then that group is on its last day of supplies.
When you travel a notable distance, lose supplies due to a hazard, give away food and water, or otherwise put a burden on your supplies, you roll a supply check. The DM determines when you make a supply check; tyically this is any time that you undergo an event that could cause you to use up a notable quantity of your food and water. When you make a supply check, have one party member roll all of your supply dice. The DM will determine the difficulty for the roll; each d6 needs to meet or beat that number. Any die that rolls lower than the difficulty number is discarded. The amount of dice that you have left after the roll determines your new level of supply.
If you run out of supply dice due to a check, you are now on your last day of supplies.
Only roll a supply check when a scene changes or an event puts stress on supplies. You don't need to roll a supply check every few days in a long and uneventful trip, just roll once at the end of the journey.
SUPPLY CHECK DIFFICULTY EXAMPLES
2 A couple days of easy travel
3 A week of easy travel
4 A couple days of difficult travel
5 A month of easy travel; a week of difficult travel
6 Supplies destroyed by environmental hazards or malice; a month of difficult travel
The difference between "easy" and "difficult" travel here is simply to indicate that the DM should decide on the difficulty for the check based on a variety of factors. If the PCs have to travel in extreme heat, over rugged terrain, while going through several battles, they will consume more resources than if they are traveling along a well-maintained road that is defended by patrols while the weather is clear and (relatively) cool.
Example: After a week crossing the desert, the party finally reaches their destination. Having set out with Bountiful supplies (knowing that this would slow them down and take longer), they roll 3 supply dice. The DM rules that the supply difficulty is a 3, because they were traveling for a week but there were no major threats to their supplies. The party rolls 2, 4, and 6. The 2 is below the difficulty, so it is discarded. The 4 and 6 are above the difficulty, so they are kept. The party goes from Bountiful supplies to Ample supplies (and now they aren't as burdened when they go into the ruins to explore!).
Create water spell: +1 to one die.
BEASTS OF BURDEN
If the PCs have mounts and beasts of burden to carry supplies, reduce the encumbrance caused by supplies by one (Ample supplies cause no encumbrance, while Bountiful supplies cause Light encumbrance), but add +1 to the difficulty of all supply checks (because the PCs must also feed and water their mounts).
Some PCs will have extraordinary ways to carry supplies, such as bags of holding, undead mounts that don't need water or rest, or construct minions that can haul huge amounts without needing to eat. The DM should adjudicate these unusual benefits on a case-by-case basis. You might reduce encumbrance penalties with no corresponding increase in difficulty of supply checks, allow the party to have more than 3 supply dice, or even choose to ignore supplies altogether if the party is able to carry a large quantity of goods without needing to worry about weight.
TO USE OR NOT TO USE?