I have quitted smoking for 3 years already. It's really hard to quit for something your body is used to for a very long time. I was a smoker for 15 years. When I felt that my body is already at the limit, I decided to stop. You need to have a focus on quitting. You need to have some alternate things to make you busy instead of smoking, like chewing candies or do something that will make your body to avoid cigarette. If you have the mindset of Quitting the habit, you will be smoke free in no time.