My riva 901 lasts about 6-8 hours with a low resistance cartomizer. With standard resistance it will last a full day. I have also read that low resistance carts/atomizers stress the batteries more. So you won't get the same life span from your battery. But the trade off is vapor production, and a warmer vape. A blank cart holds about 25-30 drops on the first fill, and it takes about 20 drops each refill. If you keep them wet and don't let them dry and burn the filler, you can get several refills on a cart. When you start noticing less vapor, you need to refill them to avoid burning them up. When they stop performing like they should and you know it is not from lack of juice then they are done for. Make sure you get some good carts and they will last you. Boge seems to be the best brand according to most members here. I haven't been able to get my hands on any for the 808d-1. Everyone buys them all up.