I have always had two cats at a time. The reason being that they keep each other company while I am at work, and they have a buddy (or nemesis as sometimes happens) to play with.
I have never had three cats all at the same time before. We adopted Mollie last year, she fitted in pretty well and pretty quickly. Our family is now Fluffy aged 11, Ziggy aged 5, and Mollie, aged 3.
When you tell people you have one cat, or two cats they never remark on it. But when you tell someone you have three, they definitely do react. ‘Three? So you really like cats!’ or ‘Three? You are definitely a cat lady’. So I guess that three and up is more unusual?