Please explain the pro's and con's to a refillable kit and a non refillable kit. I have a non refillable kit and it's quite convienient for me. I don't have to refill anything all I do is take a couple cartridges with me if I'm going out (just to be safe normally don't even go through one). There is a lot of talk about a refillable kits on here seems like it may be a hassle to continually refill, especially the ones that need a syringe to refill and sounds like it can be very messy. Please elaborate more would appreciate it. Thanks