I've been using mine (purchased from Vapor Kings) for about 2 months now, ever since they started selling them. I'm on my 3rd carto (technically 4th, but I burned up my first one by being silly and using it on 4.5 volts before it was broke in) now. I get about 3-4 weeks per carto, which translates into about 20-25 ml of juice per carto. I think if you use higher voltage it will die faster, I found that when I used it at 4.5 (after being broken in on 3.7) it lasts about a week less vs constant 3.7 voltage use. Other than that, I love it! No leaks yet and at only 12.99 a pop when or if it starts to leak, toss and buy a new one!