I actually do kind of know though. I've seen many different types of smokers. The bartender that always had a cigarette going, maybe one at each end of the bar on occasion. A painter buddy of mine, always with a cigarette dangling while he worked. I'd say they never actually smoked all of their cigarette like I did. I was never one to habitually be smoking all the time and almost never when I drove. My pack-a-day of strong ones, the way I smoked them, may have been very close to another persons two packs in reality. I always stopped and took the time to really smoke all of one, almost never finding one burned out in an ashtray.
As a teenager one day, home alone, I actually resolved to see just what it was like to smoke a whole pack in one day. I was still at the stage of thinking it was cool and envious of adults that could smoke whenever they wanted. I knew a pack-a-day was pretty normal and was going to find out what it was like. At a stage of maybe four or five a day at 15 or so, that was quite a leap. It was actually kind of a chore. I never got to a pack-a-day until I was an adult and out of the house on my own and never went over that limit. Most days it was under a whole pack.
It is really a shame that they are so bad for us. Were they cheap still and only minimally risky, I'd say you'd be crazy to not smoke them. Risk is the wrong word though. Anyone that smoked for even a few years knows, even if they deny it. The first time I got caught by my mom was smoking a cigar. The best thing she could have done then was to lecture me about ever smoking cigarettes but have given me permission to smoke cigars! If that would have worked, I'd be better off today. The difference between inhaling smoking cigarettes and just puffing on cigars is huge. Probably close to the difference in smoking pot to firing up heroine.