Eggs at the store are labeled "best before" or "sell by" for something between 30-45 days. I've eaten eggs two plus months old. They just dry out and are best made with milk added. I personally don't wash eggs till eating time, and wipe clean with a towel if soiled.
I don't wash my eggs. If they are dirty, I'll wipe with a cloth, but only right before I cook or sell them (except for the occasional really poopy egg, which goes to the dogs!). I just don't see the point as they are really clean naturally, but if you need to wash them then refridgerate it can't hurt.
Usually the only dirt they have is from the little hands that collect them, and that has been cut down on significantly by sending the kids out with an egg carton to collect into. We've even had eggs in pockets that got forgot about and crushed!