Momentum compounds when decisions become routines.

Every decision costs something, and the ones you make repeatedly cost the most in total. Converting a recurring decision into a routine removes it from your day permanently, and the attention freed goes somewhere else. Do this with several decisions and the accumulated saving becomes substantial, which is why routine looks so much like productivity from outside.

Find one thing you decide every day, when to exercise, what to eat, when to handle messages, and fix it. Choose once and stop revisiting. The point is not the choice itself but never having to make it again.