I started at 18, went to 24 chain vaped & wasn't satisfied. Then went to 30, now I'm ok. I plan on weaning back down a bit because the 30 is almost too much. almost. lol At least now I put the pv down on occasion. Oddly enough, I wasn't that heavy of a smoker. about 1/2 pad. Then again, I smoked pall mall menthol 100's for years and thought nothing of it. I'm happy where I'm at right now. I also deal with having serious chronic depression, so I am sure that ups my nic needs too.