What goes wrong when you ignore that habits reduce willpower requirements?

The most common reason fails: Attempting to habituate everything at once and collapsing under the initial willpower cost of building multiple new habits simultaneously. Each new habit requires System 2 investment during the formation period. Trying to install six habits at the same time depletes the very resource the habits are meant to conserve, and all six fail. The failure mode is impatience — wanting the willpower dividend before paying the formation cost.

The fix: Identify five daily decisions you make repeatedly — what to eat, when to exercise, what to wear, which tasks to start first, when to check email. For each one, design a default: a pre-committed choice that eliminates the decision entirely. Implement one default today and run it for seven consecutive days without deviation. At the end of the week, note two things: how much mental energy the default saved, and what you did with that freed capacity.

The underlying principle is straightforward: Automated behavior does not require decision-making energy.