One of the best reasons to refinance is to lower the interest rate on your existing loan. Historically, the rule of thumb is that refinancing is a good idea if you can reduce your interest rate by at least 2%. However, many lenders say 1% savings is enough of an incentive to refinance. Refinancing a mortgage involves taking out a new loan to pay off your original mortgage loan. In many cases, homeowners refinance to take advantage of lower market interest rates, cash out a portion of their equity, or to reduce their monthly payment with a longer repayment term