There is no "usual" as all cats are different, but I did a search on Pet Talk when I adopted Mishi and looked on the web too on how to introduce a new cat to the resident cat(s). The "norm" is about a week or two. I was advised to keep them completely separated for a week and then to slowly introduce them to each other with supervised visits for an hour or so a day. It worked for me - two weeks was all I could stand to have one or the other locked up. Of course the first time I left them unsupervised while I went to work, I was a nervous wreck, but there was no blood when I got home It's taken my two a long time to get cozy. They're FINALLY sleeping together, although not all the time, That's ONLY taken two years