You have finite amount of willpower that is depleted when exerting self-control or making decisions
You use same supply for all temptations / decisions
Only way to restore your body’s willpower is by eating foods that have glucose (sugar) or by sleeping / resting
You can strengthen willpower by forcing yourself to maintain habits that require self-control (e.g., flossing, cleaning your room, making a new habit)
Save your willpower energy by simply avoiding temptation in the first place through habits or automatic rules; avoid wasting energy on trivial decisions; other tricks exist too…