I started out as a social smoker when I was 14. Not really smoking on other times than when I was drinking & partying.
At 16 I moved to a dorm and began to have a few cigarettes on random social occassions, and then I soon grew custom to smoke a cigarette after each school day, which then escalated to smoking a few in a day; after meals, before & after school and so on. Some time after that, I was smoking a pack of 20 in two-to-four days. I was definitely hooked by then, but I managed to not smoke during most weekends from 16-19 years, because I didn't want to give bad influence to my then-girlfriend's younger siblings.
I'm 23 at the moment, so I've smoked a bit over seven years (that's a bit depressing statistic), and I've been smoking about a pack a day for the most part of that time. On one summer I had the dullest job with averaging 15h work days, where I smoked two packs a day. Also, when I'm drinking (or completely bored or driving for long) I do tend to smoke a lot more than just a pack a day.
My parents were smokers, so I guess that has had an influence. As well as a somewhat addiction-oriented personality. About a year ago I realized the full effects of my smoking. The (actually not all that major) physical effects being more or less evident, the mental and other effects have been quite vast.
I had a few half-assed attempts to quit smoking, not long after I was hooked, and it goes without saying that nothing came out of those. At best, I quit for a week, went on to run a few kilometres, coughed my lungs out during it and got back to smoking after that run. The last time I tried, I went cold turkey and couldn't continue after three days. I went through such massive amounts of anxiety, followed by awful restlessness and depression that I couldn't handle it. That's when I decided to not try the next time, but to go through it only more time, and quit.
I know a relative couple who only smoke the 0-5 cigarettes a day, and have done that for years, or for a bit short of two decades, and they've got no problems with it. Whereas that's only been my addiction's constant bargaining while trying, or just planning to, quit.
So, OT: some odd people can do it, but definitely not everyone. My attempts for moderation have not worked in the slightest in practice, even though it's a rather simple idea.
I have a quite unorthodox job, which I'll stop to have some free time prior to going back to school in a few weeks, and I've already decided early this year, to quit smoking, as soon as this work thing and living in hotels is over. No I've only got to stick to it, find heaps of more motivation and to try every trick in the book.
Smoking is bad mmmkay. I sure as hell wouldn't have been doing it for the last couple of years unless quitting weren't so fucking difficult.