Extenuating circumstances had us moved in together after 5 months. It was a finances thing on both our parts, on top of the fact that I was over at his place nearly every day, all the time. My poor cat felt lonely without me and dealt with a lot of alone time
In an "ideal world," we both admitted that we wished we could have waited until 6 months at least.
But we've been living together now for 4 months and things are going swimmingly.
I was getting cold feet right at the last minute, which was weird for me, but then I realized that everyone's relationships are different and not everything goes on a perfect cookie-cutter timeline.