When I was vaping 24mg, it was just fine until I started vaping a lot, then I was getting way too much nic, and was having trouble sleeping at night. So I cut it down in half to 12mg, and that was just about right. I ordered a bit shipment of e-juice that when cut down took it to 9mg, and I figured since I was doing only 12mg at the time, it wouldn't be too much of a difference.
Now I am thinking about tapering down to zero nic within a couple of months, just so I can say I am nicotine free, and can pass the little nicotine test the life insurance company gives and get a reduced rate for being a non-smoker.
So a little of both.