These days most people request a Good Faith Estimate (GFE), but have no clue what to look for on the GFE. Make sure you request a GFE that has ALL fees estimated and disclosed. This includes: origination points, processing, lender, appraisal, title, escrow... ALL FEES... especially the Yield Spread Premium or YSP.
If your property value reduces and you refinance up to 80% of the reappraised value, your original mortgage amount may be higher than this amount. Thus, the new loan will not be sufficient enough to help you pay down the existing one.
Don't rely on published rates. "No one's going to advertise their worst product," says Keith T. Gumbinger of HSH Associates, a Butler, NJ, firm that tracks mortgage rates. "They advertise the best possible rate, which probably gets offered to only the top 10 percent of applicants."
If there is a big difference between the initial interest rate and the APR listed in the ad, it may mean that there are high fees associated with the loan.