With a 30-year fixed-rate mortgage, your mortgage rate stays the same for every one of your 360 monthly payments. The benefits of that feature become apparent over time: As overall prices rise and your income grows, your mortgage payment stays the same.One twist to 30-year mortgages comes from the calculus behind the amortization schedule: In the early years of a 30-year loan, you pay much more interest than principal. Learn more: Guide to fixed-rate mortgages