I've tried to quit numerous times over the last twenty years or so, and have lasted for over six months on a couple of occasions, but I always buckle in the end and go back to the smokes. That's usually when something really stressful happens (major family illness) and my first reaction is to get down to the corner shop for some cigs and a lighter.
The last 3 years or so, though, I've not been getting any joy in my attempts to quit. Tried cold turkey, which has worked for me before, but no luck. Tried the inhalator things, which worked fine the one time I tried them before, but didn't work for me. Didn't bother trying the gum (nasty stuff) or the patches (don't help with the craving, but do give me a nasty rash).
So I got one of them e-cigarette things I've heard a bit about, lately - and it's doing a great job for me.
I hear the success rate is comparable to other methods - I guess some quitting methods/aids work better for some folk, and it's down to the individual - but I've not had a single cigarette since around 9pm on Saturday 22nd March, and I've not really missed them much.
Naturally, I'm still addicted to nicotine. This thing has kept me on the nicotine but switched me from cigs (definitely harmful and ridiculously expensive) to vapour (long term health effects not conclusively known, but probably safe, and relatively cheap).
At some point in the future I might try weaning off the e-cig, but for now I'm in no rush. I'm happy to keep using it indefinitely.