Habits run on clues: a time of day, a place, certain people. Change one clue and the habit gets weaker.

The strength of a habit sits in its clues rather than in how much you want it. A time, a room, a chair, a particular group of people, the exact moment you walk through the door: those are what trigger the thing before you have made any decision. They are doing the heavy lifting, which is good news, because a clue is easier to move than willpower is to summon.

So change the place rather than the plan. Do your homework somewhere other than your bed, leave the phone in a different room, take a different route past the shop.