The nic helps simulate smoking. For some, the whole physical thing is enough. I was a menthol smoker, so menthol gives me the TH already without the nic. I use nic only when I use other flavors. 6-10 mg does it for me, or maybe less as long as it is at the point where I could sense even a hint of it. I don't intend to go zero nic and I don't worry about it. I could always cut down my vaping anytime if it begins to concern me. I'd rather smoke an analog than vape without nic. OR stop vaping completely.