I'm down to 3mg nic. I use 0.6 ohm coils in a RDA, and 0.25 ohm coils in my Crown clearomizer tank. I'm pretty much a chain vaper, basically because I can. I'm retired and enjoy vaping.
I probably could get by not vaping as much if I increased the nic level, but that would make the vapor a little more harsh. I like a smoother vape that's not harsh. 3mg seems to be my sweet spot.