A workweek system is not a thing you set up once and keep forever. It drifts. Scope creeps, the batching slips, a deep block gets eaten by a recurring call that should not exist, and three weeks later you are back to reactive without ever having decided to be. Every system decays unless something forces it back into shape, and the thing that does that is a weekly review.
It is fifteen minutes and you run it at the end of the week. You look back honestly: did the important work actually get its hours, or did the urgent eat it again? What spent more time than it deserved? What kept interrupting that you could batch or kill? You are not judging yourself, you are reading the instruments, the way a pilot scans the panel rather than guessing the altitude.
Then you look forward and set the next week up while this one is fresh in your mind. Pick the two or three outcomes that matter, block the deep work, defend the windows for the shallow. The review is the seam between weeks where you correct course, and a course corrected every seven days never drifts far. Skip it for a month and you will not notice the drift until you are badly off track.
This is the keystone habit, the one that holds the other six together. Plan your days, protect your blocks, batch your inbox, say your noes, theme your weeks, and then once a week step back and check the whole machine is still running the way you designed it. Fifteen minutes buys you a week you actually ran instead of one that ran you.
