When I first committed to a path of self-development and lifelong learning, there was a quote by the father of American psychology that I thought about constantly.
William James, in his book habits, “Never suffer an exception to occur till the new habit is securely rooted in your life. Each lapse is like the letting fall of a ball of string which one is carefully winding up; a single slip undoes more than a great many turns will wind again. Continuity of training is the great means of making the nervous system act infallibly right.”
A habit is only as strong as the last instance in which you did it. Even a slight slip-up will undo more than a “great many turns.”