I've only smoked for about 6 years and tried to quit, maybe 5 or so times. I found the only time I quit for anything longer than days was when I gradually reduced what I was smoking day to day. It took me a few weeks but when I stopped the withdrawal wasn't quite as bad.
I've seen some articles mocking this method, saying withdrawal will drag out and you'll fail. I disagree as I've found quitting cold turkey causes me to go absolutely insane until I start again to make it stop.
I need to quit, and I'm planning to start it by this method again since it's the only one that's ever worked. I tried the patches and gum before and those didn't help at all.