From the posts above, overscheduling seems to be partly defined by how much the parent has to schlep around. If I had 2, I couldn't have DD in the programs she is in.

There was a mother of one of DD's classmates last year who is a ped GI. She works at a hospital one hour away and has 4 children. We were on a field trip together and talking about activies. Their piano practice was limited to 15 minutes because that is what she could help them do. DD does scales for 15 minutes. She has to do them all then contrary.

So it also depends how much time the parent can give to activities.