The most severe habits can be broken in 66 days. This was summed up in a report by University College London researchers.

According to their analysis, each new habit is formed over a period of 2 months, for some people it may take only 18 days and for others it may take up to 254.

By "habit", researchers mean any type of human behaviour that goes by a particular pattern - eating and sleeping, smoking, resting methods, etc.

Scientists say that humans quit smoking faster if they are threatened with a dangerous disease.

Prior to the last fundamental study, it was thought that a habit is formed for 21 days. At least that's what plastic surgeon Maxwell Maltz said in his 1960 book Psycho-Cybernetics. Then he discovered that his clients needed just as much time to get used to the plastic changes on their face.