Me, I started at 18mg, but with diy and better tanks, settled in around 14mg (MTL). Never felt quite satisfied when I dropped to 12mg. I'm not trying to reduce, but don't really want to increase.
A while back, I upped the nic to 20+, to see if I would vape less. Didn't really work for me. I learned that most of my hits during the day are from habit, not feeling a need for nic. So now I'm back to 14.
But I'm still experimenting with higher nic juices just for my pods. I have a 36 mg that's half FB & half salts that's working pretty well, but I think I can drop it by reducing the salts. I need TH, and FB gives more, but the salts do add something flavor-wise, other than just nic hit. Problem is that each pod hits different, and I'm trying to reduce volume thru them, because NET kills a pod so fast. When I finally settle on A pod, I'll probably tweak the juice to something higher than 14, though, since they just don't do what a tank does.