I think that's a pretty thin line. I started out social smoking and then sure enough before I knew it I was chain smoking.
I'd even go play full court basketball every other day for hours at a time, even as a smoker. Doctor told me that I was crazy and I was destryoing my lungs, kidneys and God knows what else. Anyhow I quit. It was very hard. It even got to the point where I'd jones and go buy a pack, smoke a couple, feel guilty then throw away the rest of the cigarettes. It was stupid and expensive.
Then one day at the liquor store I saw a homeless guy come in and ask for 1 cigarette for .25cents. I thought.. hmmm... So I'd come in whenever I needed a nicotine fix and have 1 cigarette. I'd buy one a day then it became one every other day and eventually one a week until I was OVER IT. It got to the point where my liquor store guy would not even sell me one. He actually helped me quit. Who would have thought.
But like campbellcj said, it is up to you and only you.
I smoked for 8 years pack or two a day, and even to this day most of my friends still smoke. Me, I don't even flinch. Good luck to those who have WILL POWER.
Don't get me wrong I'm no staunch anti-smoker hating smokers now. I know what a good buzz is..