Changing takes one decision and about a thousand reminders.

Deciding is the easy part and it happens once. What actually carries a change is the reminding, which happens constantly and feels unglamorous every time. Your brain will not hold the new plan on its own, because it is still running the old one by default. Needing the reminder again is not weak willpower but the ordinary shape of change.

Build the reminders into places you already look. A note on the mirror, an alarm labeled with the actual thing, the shoes by the door. When you forget, reset without a verdict about your character.