I smoked for almost 20 years. I lost track of how many times I tried - and failed - to quit. Last December I just felt done. Put it down and haven't gone back to it. I even had a few cigarettes while out with a friend in March and had no desire to go back to it after. I know a few other people who quit like that, but far more who have struggled with it for years and still smoke.
I have no idea what changed for me. Every other attempt failed, even if I felt really ready to quit.
This is my story, too. I'll have a few if I go out to a bar, but I'm done doing that shit all the time; having to go outside when I'm home, in my car, sneaking out at family gatherings, etc.
However, if I were to return to hanging out at bars a lot, I would absolutely become a full time smoker again.