I think people here have hit on some pretty good points. It's courteous to hold onto as few acceptances as possible, but sometimes it takes a while for financial aid info to come back. Also, waiting for non-rolling acceptances can be a factor. I'm holding onto 4 acceptances until I get financial aid info and news from my non-rolling schools. I don't have a definite "first choice," and I would seriously consider going to any of the schools where I was accepted, so I don't want to give up any acceptances until I hear how much they'll cost me and whether I got into Pitt and Penn. In my case, I'd pick either of these 2 non-rolling schools above a lot of the schools where I was already accepted, but I have to hang onto the rolling schools in case I don't get into the others. I don't know how many other people are in the same boat, but I figure there will be a bunch of withdrawals after the non-rolling acceptances come out in March.