I also believe it’s the duration of use and not the concentration of use that plays more a role here. Being a heavy smoker for 4 years isn’t the same mentally as someone who smoked normally for 20 years. I think past the 10 year mark and your brain has suffered damage to the point where the addiction becomes life. However, in about 10% of cases, smokers who quit were able to because the effects of nicotine addiction hadn’t taken hold. Much like some people feel nothing from taking cocaine.

IANAE though.

Either way. I was a smoker but not a heroin user and quitting was the hardest thing for me. It took me almost a month to feel normal.

WOW that's amazing how different people's experiences can be.

I smoked one pack spread out 2 or 3 days, for about 3 years (in college). Rarely would do a full pack in a day.

Quitting was pure torture. I stayed up 24 hours walking laps around my campus. Took like four full days for cravings to go away.

Haven't had a cigarette in 10 yrs. Occasionally enjoy a cigar without problems

I was terribly addicted for a decade, smoking and then vaping, and for me, withdrawal was almost intolerable. For about three days, it was a terrible experience. I felt sick, raged with anger, cried, felt unhinged, and even had minor visual disturbances. It can really only only be compared to a bad psychedelic trip. But once I did manage to get through it, that was it. It hasn't much bothered me since. Stopped thinking about smoking about a week after. I can't say I crave it really, and I cannot relate to the long-term experiences where people say it takes months or years to get fully over it. We're all different.