I couldn't tell you yet, about my usage. I think I vape a ml and a half a day. Seems to me to be on the light side. There are circumstances that may askew that number. I have a handful of 10 ml's now, as they had a sale at vaporbomb. I bought them for the same price per ml as a 30 ml bottle, so I went with variety this last time, but I digress.
I'm dripping right now with my ego-t, due to an accident with the atty. Seems to me that 3 or 4 drops will vape like I was smoking a whole cigarette. If I keep to that, and not chain it all day, I would think 10 ml would last quite a while. I'll do that with a single 10 ml bottle and post back.