i'm terrible with quarantine. like twitch, i dont have a separate airspace in which to do that, and changing clothes and showering a million times a day is a pain in the butt, but i will try to keep them apart for at least a week before trying to introduce the new ratties to the existing ratties.
ginger & loco came from the same store at the same time so that wasnt a problem. soot & ash came from the same store but 4 days apart so i just put ash in with soot as i know they were cagemates in the store. i kept both cages at opposite sides of my apartment for about a week and a half, then put the cages closer together so that they could all see each other. much huffing and puffing later, i put them all onto my bed and they just played with each other like they had been friends all their lives.
when i got meggsy, i put soot & ash in her cage without worrying about quarantine as meggsy had been a solitary rattie all her little life and her previous person had scrubbed her cage before giving them to me. a little sniffing and they are already best friends. all five of them love running around on my bed or freeranging in my living room.