There have been times (like when we were moving) when they had to share less boxes, and they also did fine with that! I think some cats are better with being in colonies. Only one of the four gets possessive over his box. The others don't really seem to care if another cat uses their favorite box or not

I had one cat going into the relationship (which was enough for me)

My husband had 3. He had a pair for about 10 years, and then a very feral ten-week-old kitten ended up in his apartment. That kitten is now four years old

I would like very much for us to find a new home for the stray, but my husband has been avoiding it. We tried, once, and the stray ended up biting the new owner so badly that they required medical treatment. He hasn't bitten anyone else, but the concern is that the next person won't return him to us if he gets aggressive and might opt to have him put down. So... seems like we're stuck with four cats