I dedicate juices to each one. At first I cleaned by just taking out the metal tube and rinsing and blowing it out, but I've since taken off the entire plastic tubing as well. The wicks always tend to get back to an almost white color. Occassionally I might moderately dry burn the coils. So far, they can last over a month. But then, I don't vape anything thicker than 70/30.. if that. Most of it is Halo juice, which are all probably in 80/20 range. Lifespan is the least of my complaints with the CE3s. Their downsides, as far as I'm concerned, is their performance at high voltages or thick juices. If they're leaking, I'm pretty sure it's user error. We all know to fill upside down (on the bottom coils), but if you're still getting leaking somehow I'm confused. The only leaking you should expect on a refill is the very last of your liquid (from the last fill) needs to be blown out the bottom end before you screw it back on the battery. It shouldn't be much more than a drop or so that comes out. After that, you should be good to go.