I was a pack and a half smoker for 23 years. But even then, I smoked around certain routines. I'd smoke more during leisure time than during activities or work, for example. I find that I tend to vape along the same lines. At work, even though I COULD vape on the job, I don't. I step outside just like when I used to smoke. It's part of my routine (and it gets me away and into fresh air for a few moments). At home, I seldom don't have one of my setups in my hand.
All told, I go through 2 mls a day on work days, and probably 3+ a day on off days.
I do vape less while driving than I used to smoke. Probably because I can't let an ecig dangle from my lips like an analog.