To determine how much you'd save, go through the following steps:

1.Calculate the total cost of the refinance, including closing costs and fees

2.Now calculate your monthly savings due to the refinanced lower interest rates

3.Divide the first number by the second number. This is your break-even time, and the number of months you'll have to stay in your current home to break even on a refinance.

Certain situations, like loans with a balloon provision, can force you to refinance. If you know you're going to have to refinance, don't do anything prejudicial to the refi (like take out another mortgage) and do the refinancing a few months prior to the balloon payment's due date.

Always speak with a mortgage professional before making your decision. He or she lives mortgages, and can almost certainly save you time and money.