2. Eliminate the Introduction Period.
When you ask someone who introduces a new cat into the family to an already established one, they will say it’s difficult. Having two cats that are already familiar with each other eliminates the introductory period, as most people that only get one end up wanting another one later on. Cats can be extremely territorial; you can avoid this hassle by adopting two cats that are from the same litter. You may need to encourage them to stay close once they are adopted, but some effort and the feeling of being secure is all they need.