Actually, nicotine has a rather short half-life of about 2 hours [1], which means even smaller doses quickly restore it close to previous levels. So in essence, tapering off is like going through many shorter withdrawals (doesn't sound scary but its actually a bit of a torture compared to quitting cold turkey).
My withdrawal symptoms don't become noticeable until the 4 hour mark. Quitting cold-turkey from a high daily intake level can be quite difficult for some people, who have intense emotional reactions. This doesn't happen for everyone, so those that say "quit cold turkey, I did" don't know how bad it gets for some. If I understand right, it's about how fast normal dopamine production recovers. https://en.wikipedia.org/wiki/Nicotine
Edit:
> which means even smaller doses quickly restore it close to previous levels
Not for me it doesn't. I'm quite aware of how much nicotine I have in my system and what effect it's having.
Smoking addiction combines both chemical addiction and a very peculiar habit. It is hard to break both at the same time; so best practice for quitting is to first drop smoking as a habit (while not touching nicotine addiction, replacing it with another nicotine source) and only afterwards working on the actual stuff.
