Lately I seem to have more appraisals "waived" or done as "drive-bys." It is interesting when those happen. It is always related to "loan to value" on the property. If your property is in a neighborhood that has an enormous range in values, and your property may be at the higher end, it isn't always beneficial to have a drive-by because you may not get the correct, higher value. Here is a good article on the ins and outs of why a lender requests a certain type of appraisal.
Median Price in San Diego Hits All-Time High