[tommychillfiger]

A factor that I've slowly started to think is potentially very relevant is age of first habit formation. Not just a puff here or there, but the age at which you were first addicted. Extremely anecdotally, I have asked people and noticed that all of my friends who can't quit started much younger in their formative years than the types who can smoke a few when drinking every now and again but otherwise abstain with no issue.