You can always get a 30 and pay extra. Why give up that flexibility. In today's market interest rates are so low the difference between the 15 and 30 rate are negligible. Also, ask yourself why the bank wants you to take the 15? It's because they make more money that way. Nit from you directly but they have more money they can loan out the faster you pay it back. Plus they have leverage with the fractional reserve system.