As far as nicotine goes, even a light cigarette gives you a lot of nic if you smoke a pack and a half a day. To get at least that much nic from vaping you could probably use 18mg but 12mg is close enough. It all depends on how often you vape. If you vape more than you used to smoke then 12mg is plenty. If not or you feel like you need a little bit more then get 18mg. Same goes with heavy smokers who smoke stronger cigs. They might want 24mg to start out with or 18mg. Anything above 24mg is entering an unsafe zone and 18mg is medium high.
