For me, smoking was no problem. A couple days of withdrawal symptoms (headache) and then mild relapses many years later at times of personal weakness/stress.

Alcohol was/is a much more sinister addiction for me. I literally have a voice inside my head that speaks to me about "dancing with the genie" (drinking, just this once). The formal withdrawal symptoms lasted about two weeks for drinking, but I didn't feel the release from the craving for another two months or so. Two years in to my abstinence, I rarely feel the urge or hear the genie's voice. However, I know that she lives inside me; waiting for a moment's weakness to unleash her hell.

The real key to beating back any addiction, in my opinion, is proper motivation. Do you REALLY want to quit?

Godspeed in fighting your war. You can do it!