I have been clean from tobacco and drugs etc for most of my life. Growing up I hated smoking, my dad smoked quite a lot and it would piss me off at times. I vowed to never smoke my entire life...and I have to say I never did during my teens when people are very easily getting into this habit. But all that changed in 2006/07.
Started smoking shisha with friends after I turned 20, had my first cigarette at 21 - it was a Benson & Hedges if I recall. I think I have had something like around 30-40 cigarettes in the last 2-3 years. One would regard me as a 'social smoker' since it has mostly been around friends or cousins who do smoke. I once had 10 cigs in 2 nights with my cousin a few months back, and then smoked a pack of Goldflake last week during work (2 a day).
But I have gone months without the need of cigs, however I seriously miss doing Shisha. Last time I had it was back in January 2009 with my best friend in uni.
So yeah, I would say time to time.