After 9 months or so, im at 2-3ml at 30mg.
But there is no normal really. On a HV mod you burn more. On LR atties, it goes quicker. Etc.
As far as how many pulls and sessions and whatnot...well, for me, it doesnt really apply. Smoking was easy. I had preset times for smokes. Usually determined by social graces. After dinner, during lunch breaks, merge it with bathroom breaks, etc. Since going to vaping, i dont have to worry about that, so i basically just take a pull here and there all day long.
Realistically, there is no normal. Go with what works for you.