Psycho-Cybernetics, basedona term he defined as, “steering your mind to a productive, useful goal so you can reach the greatest port in the world, peace of mind.” In that book, Maltz discussed the importance of routine and habit as crucial to productivity, writing, “These, and many other commonly observed phenomena, tend to show that it requires a minimum of about 21 days for an old mental image to dissolve and a new one to gel.”Out of that innocuous sentence, which he loosely based on observational studies of himself and his patients, was born what is now widely accepted as fact: It takes 21 days to make or break a habit.
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