When a person has, for some reason or another, allowed muscles to decrease to the point where they literally can't use them, they go through a long process of therapy, gradually rebuilding the strength in those muscles until they can use them without assistance. It's not impossible for this to happen with self-discipline; someone who once possessed plenty of it can allow it to decrease by failing to use restraint and letting bad habits commandeer their life. I know this happened to me, and it wasn't easy to fix. There is a point where you let your self-discipline weaken so much that it's impossible to get it back without outside assistance. That point is where accountability comes into play; having someone to push you and force you to do what you can't force yourself to do. They keep you accountable for each action, and not only give you an angry stare when you fail, but ensure you don't fail in the first place. The key is to find someone who's going to be present in your day-to-day life enough to help you. If you're working on a new habit for your work life, then they only need to present at work.