The final version of the Supplies rules before play begins, for anyone interested:
Supplies-
As opposed to tracking mundane things such as rations, ammunition, or non-costly spell components, characters instead have access to Supplies.
A unit of Supplies has a value of 5 silver pieces and weighs 2 pounds. Supplies can be purchased in most communities or gathered in the field.
Use of Supplies-
Whenever a character wishes to take a Short Rest, they must consume a unit of Supplies. This includes eating, bandaging minor wounds, and performing basic maintenance on their equipment.
Change to Short Rests: characters need to have one unit of Supplies to take a Short Rest, which are consumed at the end of the Rest. The idea is that you're maybe having a quick meal or snack while you rest. A Short Rest takes 10 minutes to complete. While taking a Short Rest, characters can Use Objects, Hide, Search, or possibly use some Class Features. Other Actions may be taken with DM approval. A character can normally only take up to 2 Short Rests per day.
Whenever a character wishes to take a Long Rest, they must consume two units of Supplies. One unit is consumed at the start of the Rest, and the second at the end of the Rest.
Clarifications to Long Rests: During a Long Rest, you can take most Actions, but are unable to cast leveled Spells. You can normally only benefit from a single Long Rest in a given 24-hour period, and you cannot take 2 Long Rests back-to-back (but see Full Rests, below). Completing a Long Rest allows you recover a number of Healing Surges equal to half your total Healing Surges (round fractions up). You may spend Healing Surges to recover hit points at any point during the Long Rest period (even if your rest is interrupted). Further, you remove one level of Exhaustion and a level of Strife when the Rest ends.
Interruptions: being interrupted does not necessarily make you unable to complete a Rest. Normally, if you are forced to take Action or damage that would prevent a Rest, the time needed to complete that Rest is simply increased by 5 minutes for a Short Rest or 1 hour for a Long Rest. If, however, the interruption is longer than 10 minutes (Short Rest) or 2 hours (Long Rest), you must start the Rest all over again.
If you find, after beginning a Long Rest, that you are unable to complete the Long Rest in a timely fashion, you need not consume the second unit of Supplies and claim instead the benefits of a Long Rest.
Failure to Rest: if you fail to take a Short or Long Rest in a single 24-hour period, you gain a level of Strife (see below). If you fail to take a Long Rest in a single 24-hour period, you also gain a level of Exhaustion.
Strife-
When characters run short on Supplies, they begin to suffer additional consequences.
Strife level 1: Ammunition and reserves of spell components begin to run dry. When using weapons with the Ammunition property, you cannot score a critical hit. Spells with a non-costly Material component have a 1-in-4 chance (1 on a d4 roll) of only dealing half damage; if the spell does not deal damage, it instead fails without expending the spell slot.
Strife level 2: melee weapons begin to suffer wear and tear. Weapon attacks can no longer score a critical hit. You cannot make attacks with weapons that use the Ammunition property. Spells with a non-costly Material component have a 2-in-6 chance (1 or 2 on a d6 roll) of only dealing half damage; if the spell does not deal damage, it instead fails without expending the spell slot.
Strife level 3: armor begins to degrade, losing it's protective value. The AC bonus of Armor and Shields are reduced by 1. Weapon attacks have their damage reduced by 1d4. Spells with a non-costly Material component have a 3-in-6 chance (1, 2, or 3 on a d6 roll) of only dealing half damage; if the spell does not deal damage, it instead fails without expending the spell slot.
Strife level 4: Armor becomes useless. Weapon attacks are made with disadvantage. Spells with non-costly Material components cannot be used.
Gathering Supplies-
Supplies can be scrounged from the environment with a Wisdom (Survival) check; success grants 1 unit of Supplies. This requires 1 hour of time per check. The base DC is 10, though the player may have advantage or disadvantage depending on how plentiful the area. The DC goes up by 1 for each roll made in the same area.
Note: some features and abilities can impact the efficiency of gathering Supplies- make certain to check with your Dungeomaster!
Specialized Supplies-
Characters may find special Supplies while foraging, or occasionally available in settlements. These grant additional benefits when used. The most common form of Special Supplies are Quality Supplies.
Quality Supplies: these typically cost 5 gp and weigh 2 pounds. When a unit is consumed during a rest, the character gains the following benefits:
1- any Healing Surges spent to recover hit points during the rest add 1d4 to the amount healed.
2- there is a 1-in-4 chance (1 on a d4 roll) the character can take an additional Short Rest within the next 24 hours.
3- the character gains Inspiration.
Cooking: while Supplies consist of more than just food and drink, most species can benefit from properly prepared meals. An Intelligence check can be made before using a unit of Supplies- if the character has proficiency in Cooking Utensils, they can add their proficiency bonus to this check. With a check of less than 5, the Supplies are ruined and cannot be consumed. With a check result of 10, the first healing surge spent during this Rest adds d4 to their result. If this check is exceeded by 5, for every 5 points, add another d4 (thus a DC 30 check would provide a meal with miraculous healing benefits, adding 5d4 to the first healing surge spent!).
Other Considerations: spells can have an impact on the gathering and use of Supplies. Strife penalties might be able to be reduced with the use of magic or abilities that can repair items. Species with unusual physiology might not need as much Supplies to take Rests. Make certain to check with your Dungeonmaster if you have any questions!*
*The various things I considered like Create Water, Natural Explorer, and so on, are still written down, but I'm only going to bring them up as needed, rather than further add to my player's comprehension bloat!