There are too many variables.
It depends on if you have OK, great or exceptional cannabis that you are using.
It also depends on if it's my first session of the day?
I always get more buzzed on the first vape session of the day with a shorter session time.
Lastly it's the unit itself? I have some vaporizers that don't get the job done as well as other vaporizers.
I like good or great flavor so when the taste is gone, I'm out. Into the ABV jar for edibles. Depending on the cannabis it's usually a medium brown with some darker brown flakes. I vaporize for pain and other conditions as well. My sessions are around 15 min maybe 12 or 15 draws? I don't count. Personally I like the act of vaporizing, so I like to take my time. I'm more of a sipper, I guess.
I like to use our fave flower recreationally as well.
Most days I use cannabis but not everyday.
Edit
I do go back and finish if the ABV is still good and tastes fine for later use. I like strains that have nice flavor. I've tried some strains where I can't stand the taste -like white widow, I've tried several different batches. The effects are quite potent but the taste almost makes me sick to my stomach.