Hey moonfaced! This is something I've been catching myself think about very often!
I just upgraded to a Kanger Nebox (60w) and this thing drinks way more juice than my previous iStick 30w! I run around 30w and use around 5-10 ml a day, depending on what Im doing! Used to be able to make a 30ml last about 10 days.. Now it's about 4-5 days.
I will say, i am very happy with my upgrade, even though Im blowing through liq, it is way more flavorful!