By the look of replies it seem that vaping is not the same as analog smoking in regards to nicotine requirements. From some research I found that independent of the type of analogs the body only received about 1mg of nicotine from 1 cig, everything else burns off. So if you are 1 pack (20's) a day smoker, you were getting about 20 mg on nicotine a day. I am not sure what it works out to be in ml of a particular strength of e-liquid. But
that is to satisfy nicotine cravings. On the other hand, people that used to smoke strong analogs (M'boro reds, Camel etc) are used to a "throat hit" of high TAR content of their analogs. They were still getting (I think) the same 20mg of nicotine a day from 1 pack, but prefer to choose higher nic e-liquid because it gives them good hit effect - similar to what TAR did before.
Before I've started vaping, I used to smoke 30 analogs/day, but very light TAR (1mg of TAR per cig). Hence I am not used to the head punch of a high TAR and 16mg juice gives me good punch to the head, but unfortunately not to the throat =( I am still experimenting with different flavors as people on this forum are suggesting that "throat hit" is not just dependent on the nic content but also on the quality of the juice/flavor.
For those trying to work out the best strength - experiment. Start low (6) and increase it to high(36) - why not the other way around? If you start high, anything lower would feel "not strong enough".
That my 5 cents