I have a 7 year old only cat, with claws. Her litter box has been in the same spot for about 4 years. Because it sits on the hardwood floor I've always had a rubber mat beneath it. The last couple of years I also added a plastic trash bag between the box and wall to help catch stray litter pieces. Recently I changed litter from clay to world's best litter because of dust. Once before I changed and a couple of times after I have found poo on the side of the box or fallen over the side. Most recently, between the box and wall, I started to find a little bit of wet litter, and just tonight found a little bit of urine mixed with a bit of litter. It's possible this is been going on longer then I think. I attributed some discoloration in the floor to the buildup of clay dust, but it could be caused by urine. Maybe it's as simple as changing the litter back, but I'm not sure if it's a behavior issue or I just need a box with a taller side. Nothing else has changed. She does use the litter.