Willpower is a finite daily fuel that gets used up by earlier acts of self-control.
A 23-lab preregistered replication (Hagger et al., 2016, n ≈ 2,000) found an effect indistinguishable from zero. Baumeister's own later work moved toward motivation and belief rather than a fuel.
Treat self-control as a design problem — reduce the number of decisions and the friction — rather than as a battery to be conserved.
Every law on Useful Mind tells you how strong the evidence behind it is. The ones that failed are kept here rather than quietly deleted, because knowing which advice is wrong saves you as much as knowing which is right.
See the ones that held up