We had an older cat and got a kitten. The kitten was super wild and wanted to play 24/7. Old cat"s only escape was to get on top of tables and dressers where baby cat was too small to jump. That was ok until kitten started patrolling and old kitty couldn't even go to the litter box without little cat jumping out at her. My poor old cat was miserable and we ended up taking her to my mom's. She was much happier there with no other animals. Few years later we got another kitty and did a whole introduction process - two days with new cat in a room and old cat in the house, two days with old cat in a room and new cat in the house, swapping beds to smell each other, food beside the door so they were eating near each other. They became great friends - playing and sleeping together. When my mom passed we took in her animals and now it's a shit show! We have five boxes but all 3 cats want to use one and one cat just poops beside that box. There are nightly cat fights that the dogs try to get in the middle of. It's so loud! Cats fight, dogs bark, husband yells -which has zero impact on the fighting or barking, and i yell that his yelling is just adding to the noise. Good times....