On Second Thought, Go To Bed
The more I think about it the more I like it. Sleep re-rolls attributes.
There is a scale, the details of which aren't important and can be made up. Each tier is the number of dice rolled and whether you pick highest or lowest.
SKILL (keep 1 result)/STAMINA (keep 4)/LUCK (keep 2)
- 3d6/8d6/4d6 low - Sleep on a hard floor exposed to the elements and danger
- 2d6/6d6/3d6 low - Camping outside with appropriate preparation
- 1d6/4d6/2d6 - Low-quality indoors rest. A bunk, a barn, a sit-up.
- 2d6/6d6/3d6 high - A decent bed in a house or hotel or the like
- 3d6/8d6/4d6 high - Fancy, warm, safe bed
You could simplify this further by making them -/+2. Add that many dice to each attribute, the +/- is whether you pick high or low. So, a fancy bed would be +2 OR 3d6/6d6/4d6, keeping the best rolls.
On waking all stats are set to whatever the roll is. Eating is now linked to wake periods, not days. So, a PC may heal from provisions three times per waking period.
Thinking engines and undead can play with this variable. They might, for instance, use the original system to generate stats and then stick at that forever, only resetting to that number on resting. Or, possibly only some attributes change, like Luck for instance. Undead might never change Stamina, they are eternal, engines might never change Skill, they are designed. Etc.
This whole system links players to civilisation and the general humdrum motions of living as a person in a society.