I smoked for about 12 years, about a pack per day. I finally quit successfully last May. I have to say that I was super surprised at how great all my post-quit medical exams went. I've recovered so well that it almost seems a bit ridiculous that I quit. I mean, I'm happy that I did quit, but for all the evidence proving how terrible smoking is for you, it's pretty amazing how quickly you can recover from a lot of it so long as you quit young enough.