I have used this litter box for a little over a month and have not changed the tray yet as my two cats do spend some time outdoors. The litter does a good job of absorbing the odor as well as raking the solid waste, and the motor is fairly quiet.  My cats do tend to kick out some of the litter so the version with the hood would probably work better for them.  I'm glad the tray have lasted longer than expected since they are a bit pricey.  So far the product is working out well. [This review was collected as part of a promotion.]