I use 24mg with no ill effects... Smoked about 15 analogs a day until started vaping.
I rarely recommend 24mg to anyone, based on my own experience with that, as well as at least 10 new vapers I introduced vaping to. Basically, they either got woozy, sick, nauseous, but for me it was anxiety, a feeling of restlessness, and feeling very imbalanced in general.
If i do recommend 24, I always say get some 12mg in SAME flavor, cuz if you mix up a little ejuice, say 3ml, same amounts of 24mg + 12mg you get 18mg.
If this works, then you now have some 18mg to vape. BUT---if your "sample" of 18mg proves too much, now you have some 12mg juice to vape, without starting all over again.
I truly believe that the WORST thing you can do to a new vaper is to over-nic them, because in essence, that is poisoning them. ! Much better to err on the lesser side, and have it turn out they need a little higher nic, which is easily solvable.
For me, I do a combination but I like lung hit vaping
Inhalation technique with an e-cigarette
18mg was even too much for me.. when I vape I like to vape for a bit. With 18mg, I was getting too much. Looks like it's 12 for me .. Although there is a noticeable decrease in throat hit.:/
DO NOT DO THIS! I vape 40mg/ml to 50mg/ml day in and day out. Cant even think of vaping 36mg/ml I would jones for sure.
I make e juice for friends and family from zero nic to 24mg/ml no one I know can or does vape at as high nic level as I do. Dont try it! Stay as low as you can to keep from going back to the stinkies.