I started at 15 and quit cold at 35. I was smoking 2 packs a day. I did a behavioral therapy class that the local hospital was hosting and one of the things they had us do was wear a rubber band around our wrist and every time the thought of a cigarette came into our heads we were supposed to snap it. Hard. I actually think that it helped to reprogram my thought patterns. I chewed a lot of gum that first year, but I never had another cigarette.