I want to give another vote to Atomic Habits by James Clear. An excellent book for understanding this sort of thing.
Also my ultra pragmatic suggestion would be: If you are uber serious about quitting, why not shave it off? That would certainly give you enough time to break the habit.
Also my ultra pragmatic suggestion would be: If you are uber serious about quitting, why not shave it off? That would certainly give you enough time to break the habit.