You should prepare to follow the program for 90 days. Why? Because behavioral research indicates that it takes 90 days to prepare for change, build a new behavior, become confident in the face of high-risk triggers, and move past the likelihood of relapse. Brain research also suggests that it takes a few months of practicing a new behavior to create permanent change.

Changeology: 5 Steps to Realizing Your Goals and Resolutions (ed. Simon and Schuster, 2013) - ISBN: 9781451657623