We try to make all the litter closets have at least 2 ways in or out. We have found with a large cat population they do not like to get cornered and some of the shyer cats will not enter areas with only one way in/out. Where design allows we have 3 ways. Cats like privacy to use the bathroom but cannot be a trap. While almost all the cats are able to climb the shelves to use the litter boxes, as they get older we sometimes have to put a box on the floor of the cabinets. We listen to the cats and always adjust things as needed. Sometimes a cat or cats will not stop peeing on the floor somewhere. After trying many things and failing to change the habit, we ended up installing another litter box right where she kept peeing. Meaning sometimes you cannot win and have to find a way to accommodate them. All the litter closets have quiet continuous fans that exhaust air to the outside. This keeps negative air pressure and the smell never flows back into the house. We use Panasonic ultra quite fans in many of the closets.