Just out of curiosity, how big would my apartment have to be for 2 cats to live comfortably together? I currently have 1 extremely mellow and chill kitten, and the apartment is small enough for it to be OK with only 1 litter box. I might be able to fit 2 litter boxes, but 3 might be a problem and 4 just isn't an option. I'll have room for 2, maybe 3 large cat trees. Is my apartment too small?