Our cats are now 17 and unfortunately keep peeing outside of the box and is going onto the floor. Its because they are getting old and are not squatting as much as they used to. Have bought 2, as have 4 cats. Were apprehensive as to whether they would use them. All great so far. The steps up are easy to use and they have to turn the corner to use, so stays within the tray. We don't use liner, as much easier without. This is also great for keeping my dog out of it too, and certainly noticed the lack of smell, compared to my previously covered boxes. The only negative we have is the lids are a bit flimsy where they join the tray, so you have to take your time to make sure it is back on correctly. Overall, wish i'd bought these years ago