Since I started using them I've had one leaking issue in like 3-4 months. I totally trust putting my eGo-T in my shirt pocket and not getting a juicy stain on it. They are more than worth their price. They are not necessarily single use either. I always assumed that the hard plastic caps leaked because of the already punctured diaphram, but that's not it at all. I use the soft caps over and over. I clean everything with alcohol anyway, so I clean them too and slap them back on at least a half dozen times before tossing.