You know, I had the exact same conversation with a couple friends of mine. Here's what happened.
Friend: So how long should I wait before accepting an offer?
Welfareballer: A day.
Friend: So tomorrow.
Welfareballer: No, tomorrow, then a day.
Friend: So 2 days.
Welfareballer: Yeah, I guess you could call it that.
Other surly friend: 2 days is like industry standard.
Welfareballer: You know, I used to wait two days before accepting anyone's offer, but now it's like everybody in town waits 2 days. So I think waiting 3 days is kinda money.
Other surly friend: 2 days is enough to show you're not anxious.
Welfareballer: Yeah, 2's enough to show you're not anxious, but I think waiting 3 days is kinda mooooonnnnnneeeeeeeyyyyy.
Friend: What if I wait 6 weeks? I'll say "Oh hey, I was going through my wallet, and I found this acceptance letter. Who's this from again?"
Other token black friend: (Laughs) Ask them if you guys did research together.
Friend: Yeah, I'll ask, "Did we do research together?" Would that be the money, welfareballer?
Welfareballer: You know, joke all you want; but if you accept too soon, you'll scare off a prestigious school who's down to work together.