Many borrowers use a refinance to shorten the term of the mortgage. And brace yourself: Even at low rates, a shorter term means a higher monthly payment. The benefit is that you'll build up equity faster and pay far less in total interest over the life of the loan.

Consider Jim Neill, 48, a real estate broker and his wife Merrilyn, 55, a psychotherapist. Recently, the couple took out a 5-year fixed rate loan at 6.75%, with a 15 ammortization period, to replace an 8.13% ARM with a 5-year term, with a 25 year ammortization period. Their monthly payment jumped by $200, but now they will own their own home outright by the time they retire. In addition, the total interest on the 15-year loan will come to $95,447, vs. $222,234 on the remaining life of the ARM -- and that assumes their adjustable rate would have held steady at its current 8.13%. "This is forced savings," says Jim. "When we retire, we can scale down and take equity out of the house."