J.O.
My oldest was done at 2 months, we had no problems, we got good earrings and never changed them unitl she was older. We had no problems. My middle DD was around 8 when we had it done (not bio)she was more traumatized by it then any of them. She knew it would be painfull and worked herself up before we even got there, but insisted on doing it, but there were no actuall problems with it, my youngest DD was done just before her 1st b-day, and again no problems.
Really it is a matter of preference, it is not hard to keep them clean and turn them.