Pay ahead on your mortgage.

This is a great way to save long term compounding numbers. Just paying ahead $20 or $100 once saves you from the interest that otherwise would be charged to you for the rest of the life of your mortgage, because you are paying off that last $100 right now. Every little bit helps. A bigger goal might be to pay your "principal payment" extra every month. This is a small number in the early years of your loan but is essentially paying 2 months every month, paying your first 10 years off in 5 years!

Don't recast. Most mortgage companies will not "recast" (when they recalculate your loan payments officially) unless you pay them to do so. When you ask them to recast, you are taking your lower mortgage amount, reduced because you paid ahead, and having them spread that payment back out across the years you had already cut off your loan. Resist! Resist!