Perhaps you want to, or have to, move. But, perhaps you still don't have a buyer for your current home. Perhaps you want to make an offer on a new place.

One way to handle this is to make your offer contingent upon the sale of your current home.

No seller is going to want to do that, even in this slower market. There's no benefit for them. They have no control over when the deal will finally close, if ever.

Instead, you may want to offer a 72-hour contingency.

How does this work? Basically, you and the seller agree on a sales price, and write up a purchase and sales contract. You put down your typical 5% or 10%. You continue to try to find a buyer for your current home.

Meanwhile, the seller continues to market his or her home, as if it isn't under agreement. If the seller gets an acceptable offer, you are given 72-hours to either agree to buy the new home, without selling your current one, or pull out of the deal, getting your 5%-10% earnest money back, no questions ask.

The seller has a bit more comfort than he or she would, otherwise. You, meanwhile, have sort of locked in your offer on a new home that you really like.

Still, this isn't that common. Too many variables.

More information: More escape clauses for buyers - By Les Christie, CNN/Money