With all the cats excretions rolling around Does the cat get dirty with its waste rolling all around the walls of this litter box? Seems like itd be rubbing against his own wast. I'd probably think twice before petting him, and letting him sleep with me knowing his fur is brushing up against this box.
If you get good CLUMPING litter that does it's job, the excrement does not "smear" around the litter box as all. I have not noticed any waste on my cat's fur and he's pretty large. I think the cats make a point to avoid touching the walls anyway. I also roll the box fully until it's completely upside down and bang the bottom.. but there is no waste stuck on the walls at all. Hope this helps!
As any Veterinarian will tell you, you should have 1 litter box PER cat in your house for this same reason. Using a good clump litter and using a pet safe spray called "Kids N Pets" will keep the smell at bay. I have 2 cats that track litter and are messy or do not cover feces. Buy one per cat it is still more efficient this litter box is not expensive at all!
This is a HUGE concern for anyone with 2 or more cats! If you do have multiple cats plan on taking it apart and scrubbing it at least once a week, otherwise the poop and urine clumps will paint the inside of the box filthy and your cats will absolutely be in contact with it as they come and go.
I only have three cats and found that even after trying to be very careful and efficient when rolling it, the inside was gross in just a day or two and the hassle of taking it apart and cleaning it was WAY MORE of a pain than just scooping!!!