Parliament Lights, about 10 a day.
I started smoking when I was 17, kind of been off and on since then, but wish I never started in the first place. I've heard people say that once you're a smoker you're always a smoker because if you quit, even 30 years down the line you'll still get cravings every once in a while.
The times I have quit have lasted about 6 months to a year, usually I start back up when I get into a really stressful situation (last time I started back up was during final exams, last semester of my senior year of college).