Pay a lump sum
A gift of money, an inheritance, a bonus or an income tax refund creates another chance to put extra money toward your mortgage. This strategy works best if you don't have other, more costly debt, Rogoszinski explains. "You really want to pay off the most expensive debt you have as fast as possible," she says.
Examples of higher-cost debt include most private student loans, auto loans, department store cards and revolving credit cards.
Another option is to deposit your windfall into a savings account and set up an automatic monthly payment from that account to your mortgage, Rogoszinski suggests. That way, you can have money in the bank and put money toward paying off your mortgage, too.
A more aggressive approach is to invest the lump sum for a return that's higher than your mortgage rate, then use the principal, plus appreciation, dividends and interest to pay off the mortgage when you retire, McIntosh suggests.
Either way, the key is figuring out how to eliminate your mortgage because that "makes the difference" between who might end up with a comfortable retirement and who will not, he says.