How many licks does it take... Oh that's another poll. I do get a lot of variety from cartomizers running time wise. They seem to last longer (5-10) days for me when simply refilling them, 3-4x per day usually. Since I got a tank, and have been punching my own the most I have gotten is about 5 days.(using them about 4v on a Infinity pro typically) They either get a bit funky after that time, or just get gurgly and drippy. I think just being constantly wet with the tank attached tends to wear down the insides of them, when you look down in a new one you can see a nice path for that inner tube , after a few days it's looks pretty closed down. I haven't really gotten any doa ones yet, I did have an incident where I had just punched a fresh one set up the tank, dripped in some juice to get things flowing, thought everything looked just right - but when I took that first hit I nearly gagged and passed out - tasted like smoking a burning carpet. I guess I punched the carto a little too hard and caused some internal injury!