I quit cold turkey a few years back, and every once in a while I still have cravings. I was never a HEAVY smoker, but my pops and ma sure were. She recently quit cold turkey been off the smokes for over a year now, and my pop switched over to the e-cigs. While I can't say what type of negative effects they have in the long run, I can tell you this, he went from hacking up a lung every night after smoking his cigarettes, to hardly ever coughing at all! I consider that in the WIN column. I'm just lucky that the cigs are so expensive now, keeps me from wanting to go back lol.