If you have a fixed-rate loan, the interest rate is set for the life of the loan. However, many companies offer variable rate mortgages, also known as adjustable rate mortgages or ARMs. These provide for periodic interest-rate adjustments. If your loan contract allows the mortgage company to adjust or change the interest rate, be sure you understand when the company has the right to change the interest rate, whether there are any limits on how much the interest or payments can change, and how often the company can change the rate. You also should know what basis the company will use to determine a new rate of interest.