Self-discipline is the crux of all lifestyle change.
Strategies, tactics, and techniques are mostly irrelevant without it.
Why? Because without self-discipline, they will eventually falter.
Self-discipline is precisely what’s needed when the going gets hard (which it will).
Self-discipline is precisely what’s needed when you face the fork in the road between: do it even though you don’t want to and let the ego come up with a totally viable and believable excuse so you don’t have to.
Self-discipline is precisely the difference between sticking the next move of the climb and falling from the boulder back to where you started.