When a property owner is considering selling his house, many times they will have an appraisal done to set the value of the property.  This can be a mistake.  If an appraiser submits a value, the owner would naturally think that the house should be listed for at least that amount.  At this point, the appriaser does not have an offer to work with and simply uses past sale that are up to 6 months old.  In the current changing market, that method may result in the owner listing the property for more than what a buyer is willing to pay.  If it is over priced, the house may sit on the market for a while as the owner continues to think that he should receive at least the appraised value.  After a while, the showings on the property stop.

I ususally recommend that the owner not get an appraisal.  As a REALTOR, we can provide not only past sales information, but also discuss current market trends and the amount of inventory on the market in certain price ranges. 

In some cases, it is necessary to get an appraisal, such as in the case of an estate.  However, if it is not necessary, save your money and get the advice of a REALTOR.