New idea, a slight twist on "spend to push" mechanics I've seen elsewhere:
Pools & Stats:
You have a pool of Energy points you can spend. This starts every day at 10, unless you are injured or poorly rested or other specific conditions.
Your Will stat is your current total of Energy points, divided by 3, rounded down. If you have the Strong-Willed trait, add 1.
Gain +1 Energy from [yet to be defined, but includes certain types of successful Action].
Lose -1 Energy from [yet to be defined, but includes certain types of failed Action].
Note: If you have the Prove Them Wrong move, you can roll that to turn a public failure from -1 Energy to +1 Energy.
If you attempt an action without attempting to Apply Will to it, then roll Skill vs Difficulty to see if you succeed or fail. You are not over-extending yourself, and the range of outcomes is fairly predictable. The GM should not embellish much beyond "it works"/"it doesn't".
If you attempt to Apply Will to an action, make two simultaneous rolls: an Apply Will roll and a Stressed Action roll. Resolve the Apply Will roll, then resolve the Stressed Action roll.
To Apply Will, roll 2d6+Will.
- On a 12+, add 2 to your Stressed Action roll, on top of any Energy spent.
- On a 10-11, add 1 to your Stressed Action roll, on top of any Energy spent.
- On a 7-9, you may spend Energy points to add to your Stressed Action roll at a rate of 1:1.
- On a 6-, you spend Energy but don't successfully apply it to your Stressed Action. Subtract Energy equal to your margin of failure (below 7).
A Stressed Action adds modifiers from a 7+ on an Apply Will roll, and then rolls on an Apocalypse World-reminiscent 3-part outcome spread: 10+ = yes, and; 7-9 = yes, but; 6- = no, and.
If you're not pushing yourself, then less is at stake. It's easier to push your efforts when you're physically, mentally and emotionally energized. Pushing yourself expends resources, though the thrill of success can gain some back. Not every attempt to push yourself actually contributes; it depends in part on whether you are already exhausted or energized. Even failed attempts to push yourself cost resources.
Replaced the Strong-Willed trait with an actual Will stat, which is modified by current Energy but not reducible to it.
When you Apply Will, spend Energy first, then roll to see how much of that Energy gets applied to your Stressed Action.
The Energy you can spend on an Action might be capped by your base Will or current Will.
Thoughts welcome, as well as accounts of your own favorite "try harder" mechanics.