66 days to form a habit?

How long does it take to form a new habit? The answer comes from a study in 2010, in which 96 people tried to form a daily eating/drinking/exercising habit. Every day, they reported how automatic that felt, so the researchers could calculate how long it takes to automatize a routine. The response was an average of 66 days. We replicated this influential study with a larger sample of 778 people (and with 4 research centers). All centers found that it took a little longer than 66 days, but the differences were so small that we consider this a successful replication.