Recommendations for introducing kittens to adult cats covers a lot of good information about introducing new kittens to a cat household.
However, we've just adopted 2 older cats (11 and 13) into our household of cats ranging from 2 to 8 years of age.
Is there anything different that should be done for new adult cats?
This answer on a different question mentions:
It's usually recommended to confine new cats to a small room (like a bathroom) for the first couple of days anyway
I have to admit I'd never heard that before; we'd done it in the past when introducing kittens, but that was almost incidental, since the small rooms were the most convenient (and a single kitten fit fairly well in there).
We've given the new cats free access to the whole basement (the bathroom seemed too small, particularly if we were going to put in two sets of bedding, food, water, and a litter pan). Was this a mistake?
They seem to be adjusting very well so far, and have explored the basement thoroughly, as well as the door at the top of the stairs (sniffing at our other cats through the crack). Both of the new cats seem comfortable in the new environment, with one of them seeming 100% at home, and the other showing some minor skittishness (but he still can easily be coaxed into a lap for some petting and purring).
Does their age allow us to do the transition more quickly? Or is it more likely to cause territoriality/dominance issues with the other cats?