I love CatGenie and would never want to go back to conventional litter boxes. I just purchased my second unit. I had the first one about 3 years and 9 months, it almost made it to three years in a one cat household. I'll admit I was disappointed when I had to start using it in manual mode because tech support and I could not figure out why it would stall a few seconds after the rinse cycle began. I got into a habit of only running it once a day (after #2) so I could make sure I was there to unplug/plug-in to restart the CPU. It worked flawlessly for three years in cat activation mode. I was thrilled that I could be away overnight a couple nights in a row without worry. When it started acting up, I could plan to be away only one night or have to ask a friend to come over to start the CatGenie and stay until they could reset it to make sure the water drained and process completed. I used the super clean cartridge as prescribed and I have taken the machine completely apart a minimum of three times since installed. This last weekend I spent an hour cleaning it. I took it outside and ran water through both ways and gave every piece a thorough cleaning. I thought for sure when I got it back put together it would work just fine. It didn't :(. Although somewhat disappointed, I realized it was not meant to last forever and in my case this is all the life I could get out it, now was the time to replace it with a new unit. I read through some other reviews and saw similar postings which reinforced my decision to buy a new unit. I feel good about it and I still LOVE CatGenie!!