I started with a 30 year mortgage in 2007. Interest rated dropped and the difference between my existing 30 year and 15 year in monthly payments for a $425K loan was something small like $300/month. I switched to a 15 year loan and then what I figured out is that the difference in loan amortization is such that if you sell in 8 or 10 years your principal is paid down quite a bit more. Particularly now that when many of us do our Federal taxes any benefit of interest rate deductions is lost and we default to the standard deduction. I would advise you to run the numbers and look at how much principal you will have as time goes on.