When cartotanks at 10w were my go-to setup I would usually vape about 5-6mls a day.
After getting into sub-ohm rebuildables my juice consumption has skyrocketed. I now vape anywhere from 10-15mls a day. I used to use those little 3ml sample bottles as my dripping bottle for when I was tasting new flavors, and it would last a decent while. Now, the 3ml bottles get vaped through in a single sitting, This morning I filled up a 15ml bottle with some Rob from MBV, it's now about 2PM and the bottle is only half full.
It's kind of funny, as I actually vape less frequently after getting into sub ohm rebuildables, but when I do vape I go through way more juice.