Okay, here's another question to the guys who answered #3, which seems to be the most popular answer.
How many puffs do you usually vape in one "setting"? By "setting" I mean the moment you pick up your PV and the moment you put it down.
For example, you are sitting there enjoying your morning coffee or surfing the net, PV in your hand, and after a certain number of puffs, you put the PV down to do something, whether it's going to the washroom, getting a book, getting a snack, or whatever. As long as the PV leaves your hand, even if you put it down on a desk right next to you, and you planning on vaping 1 minutes later, that session is done.
So how long is a typical "session"? I mean, just because you "chain vape" or vape "all day", doesn't mean you never take a break right?