I would imagine that everyone is different. You hear lots of people saying they like going back to work, as they get to do a bit of reading for themselves on the train, and get to think about something other than baby. My wife went back 3 days after our first, and she absolutely hated it. She just couldn't stand being away from the little one, although she did admit she enjoyed reading on the train! She's off again now, as our second is due in a few weeks, and after this, she'll probably go back 2 days, as she feels that would be a lot more barable.