7 to 15ml per day. But it's a questionable number. I go to work with two tanks. My adv tank and my new flavor tank. I typically walk out the door with one adv mix in a 30ml and two test flavors in 15ml bottles. If one of those test flavors hits the spot (like Fuji FA is my new favorite) I can hit 15-18mls. If my test flavor is ok I vape it as much as possible scratching my head thinking all day for a few days about what is missing ( current one is oba oba, peper, ylang and a touch of orange...needs something more'ish..don't even know what I was tying to accomplish there on that mix but odd for sure).