I think the "light switch" paradigm works for any drug with very strong addiction potential. Don't even consider doing heroin or nicotine. Cocaine _very_ carefully if you really have to.
Though to be honest nicotine is one of the hardest ones for the simple fact that it's so widespread. You can't really avoid it if your friends smoke or if it's still cool to smoke on TV (i.e. Mad Men). You don't go to a rehab or join a support group and call your sponsor whenever you feel you'd go for one, you'll be on your own. Thankfully it's getting easier and easier these days when it's not socially acceptable to smoke anymore, but still, quitting nicotine is one of the 3 hardest things you'll ever do in your life.
I have no idea. I'm just saying that quitting smoking will be one of those three. Probably not the hardest, but it's up there. FWIW it's the hardest thing I've done in my 34 years of age, it's taken me 10+ years to quit, I'm now 1.5 years nicotine free and I will have to be vigilant for the rest of my life.
Though to be honest nicotine is one of the hardest ones for the simple fact that it's so widespread. You can't really avoid it if your friends smoke or if it's still cool to smoke on TV (i.e. Mad Men). You don't go to a rehab or join a support group and call your sponsor whenever you feel you'd go for one, you'll be on your own. Thankfully it's getting easier and easier these days when it's not socially acceptable to smoke anymore, but still, quitting nicotine is one of the 3 hardest things you'll ever do in your life.