Well I did it for the first time today and he is 4 months old and there wasn't.much in there at all so I say you could wait til he's 4 months old and you do it to get rid of the gunk that builds up in there because when they drag their butts on the ground it picks up hay, fur, poops and all that stuff gets stuck in there and you can imagine how that might cause some discomfort in there and as they get older you should do it more often because they're anal muscles don't work as well and their poops can get stuck in there but while they're still ground you only have to do it once a month give or take depending on how dirty their bum is each time you clean it