I stopped drinking alcoholicly (not a drop since) almost four years ago, I quit an addiction of compulsion (graffiti) three years ago and I quit cigs over two years ago. It can be done! Now, i do still have trouble with pot, tv, junk food, caffeine, sugar and exercise endorphins. But one can't shake all of one's addictions at once. I have learned to take on one thing at a time and to start with the most destructive and life controlling. I also believe that everyone needs a vice and if one can learn moderation that vice can be quite healthy. But substances that can make an addict out of anyone (booze, tobacco and hard drugs) should be avoided by most people. 1 in 10 becomes addicted to alcohol and I have never met a "casual smoker" who didn't end up addicted. Some addictions are chemical and mental, some are purely mental but they all have physical elements.
When I was working on tobacco I quit and went cold turkey a dozen times in a year or so before it finally took. Tobacco withdrawl is the worst and it lasts for weeks at a time. I know an ex heroin user who still can't kick cigs. He says it is worse than the h.
Perseverance is what I learned by entering recovery. Never give up, care about yourself, learn from your mistakes and try again.