2 weeks, no nicotine. It's happening. Much easier once I discovered (had never been told it like this before) that life as a smoker means living daily in a state of withdrawal. Even one cigarette means that I will instantly put myself into nicotine withdrawal for at least the next 3 days. Even one hit off a vape - anything that puts any nicotine back into my system, because as soon as it is there, the mind becomes aware about 10-15 minutes later that it is not there anymore, and the psychosis of withdrawal begins again. It is the very same psychosis of withdrawal that convinces us to have the first cigarette in the morning, and the next one after that, and will kick in minutes after finishing a cigarette or any other nicotine going in your body, every time. There isn't some critical mass of nicotine, or number of cigarettes that will be OK.
So now, NOT having another cigarette means NOT having to be in withdrawal. That's it. Living life in withdrawal sucks, no matter how great the nicotine itself may feel. Recognizing this has made a huge difference in managing cravings, being in situations where I would be triggered, etc. I've already stopped using bupropion; its job is done. That was really the only thing that I used as a crutch. No tapering down, just quit. had a relapse 25 hours in, went through about 1 1/2 packs, finished the pack I bought, quit again, haven't had any nicotine since 23:30 on July 15.