I usually have 2 PVs going, one with ~18mg nic ( i have 1 24mg carto for my morning hit) and one 0 nic (mostly DIY) i puff away as long as i want on the zero nic without thought or worry. When i have a craving, i pick up my nic PV, take a couple of drags, which usually kills the craving, and back to zero nic. Vaping this way, i usually go through ~ 1ML of nic liquid, and 2ML of zero nic a day. I was a 1/2 PAD for ~15yrs.