Supply and Demand
When the supply of available houses is greater than the supply of buyers, appreciation may slow and prices may even fall, and the real estate market will enter into what is commonly referred to as a "buyer's market".
If you are lucky enough to purchase a home during a slow period or buyer's market, you can be reasonably certain the economy will begin to show strength again. At times, real estate values may even surge drastically. In many regions of the country, this is precisely what occurred in the late 1980's and 1990's.