I quit twice. Once cold turkey and didn't smoke again for twenty years. But then one day I lit up again and yep, I was soon smoking a pack a day again. The second time I took Chantix. I know about the side effects but I knew I couldn't do it cold turkey again. The drug worked perfectly for me. I had some horribly vivid dreams that were very disturbing, but I stuck it out and was able to quit. In fact, I didn't even have to take the whole course. I smoked the first week as instructed and with each day the taste got worse and worse. By the second week I was able to not smoke at all. I was off the drug within three weeks and didn't pick up again.
Now, that said, I have to admit that the craving for a smoke never really disappears for me. I LOVED smoking and I go through terrible moments of intense craving, but all I have to do is remember how I was back into my addiction so quickly after completely cleaning up my lungs. I guess I'm going to just have to miss it. . . . although if I live to 90, I might pick it up again because at that point what would it matter