If you are thinking of refinancing your mortgage, remember to shop around, compare loan terms and negotiate with lenders. Refinancing allows you to switch to a different mortgage with terms that you think are more beneficial. If your credit score has improved, you may be able to get a loan at a lower rate. Or you may want to refinance for a longer term to lower your monthly payments. (suggestion from a seasoned real estate professional like myself, at least 3 or 4 opinions are necessary).
Be prepared however to pay closing or settlement costs to refinance. Lenders are required by federal law to provide a "good faith estimate" of your closing costs within three days of receiving your loan application.
A refinancing calculator that I use for my clients is located at www.federalreserve.gov