Comment by cheald

It still requires willpower, but to use a metaphor, it's much easier to travel down a well-trod path than it is to cut a new path through the jungle. Repetition and consistency establishes the path, so the willpower required to travel down it the next day is reduced over time. Establishing a pre-set time and committing to that time ahead of time removes the "will I or won't I" decision at "go time", when you're most likely to falter.