I just got this last week but so far so good. I had previously purchased another shower filter. I didn't notice any change, but, I assumed it must be filtering out something. Then I got a rash after every shower, I replaced the existing one with a new one, but, the rash didn't go away. I called my water company and they said that they use more chlorine in the winter and recommended I try a Vitamin C filter. After using this filter, my hair is much less crazy and my rash has gone away. I have not had any problems with leaks. I can't yet tell how long a cartridge will last. But, i wish they had refillable ones to save on plastic.