I told a girl I moved in with that we have a limit on pets. Either 1 dog, or 2 cats. Thats it. I'm not going to be walking down the street with 15 dogs, and a room dedicated to cat litter boxes.
Zero cats? Maybe you need a cat.
One cat? Maybe your cat needs a friend.
Two cats? This is an acceptable amount number of cats.
Three cats? This is getting out of hand, but maybe you found a foster cat that you decided to permanently home.
Four cats? You're officially the crazy cat lady from the simpsons.