I also can vape at my desk at work and I find that if I slowly and steadily vape all day non-stop I don't ever go into withdrawal, and I don't find myself wanting a cigarette. If I ever wait until it's "time" to vape then it's too late and I get bothered and really want an analog, so I do my best to never get to that point.
I was using cartridges 100% up until 3 weeks ago and I went through 6-8ml per day. I switched to dripping exclusively and that number dropped in half to 3-4ml per day. Those cartridges really chew up some juice! Starting this week I'm trying out dripping on LR atties and yesterday my juice consumption was about 6ml...
You definitely will know if you have too much nicotine, as I got some 24mg juice as a free sample and vaped it just like I was vaping my my normal 12-15mg and got really dizzy and lightheaded. It was not a fun lightheaded and dizzy either!