Let's say you have 25 years left on a 30-year mortgage at 6% and still owe $175,000. You'd pay about $163,000 in interest over the remaining quarter-century. For just $167 more per month, plus one-time closing costs, you could refinance to a 15-year mortgage at 4% and save $105,000 in interest. And, of course, you'd be mortgage-free a decade earlier.

3. Downsize your home

Think about it: At a time when you're supposed to be enjoying the simple life, do you really need a formal living room, separate dining room and two spare bedrooms that you never set foot in? If your answer is no, think about downsizing your home.

The beauty of downsizing to a smaller home in the same area is that you don't need to say goodbye to your friends, family and community. Of course, beauty can also be found in the fact that you might be able to pay cash for your new abode. That means no mortgage.

And don't limit your notion of downsizing. Just because you spent the past 30 years in a traditional ranch doesn't mean you need to purchase another ranch with less square footage. Check out conventional alternatives (condos, townhouses) as well as unconventional options (houseboats, RVs and even tiny homes).

4. Relocate to a cheaper city

Can't find the right place at the right price to retire in your hometown? Move somewhere cheaper. Sure, there will be sacrifices, but what you'll give up in familiarity you'll make up for financially. The best places to retire combine ample activities with affordable real estate. And moving to an affordable locale will boost the odds that you won't have to take out a new mortgage.

Home prices aren't the only factor. Consider property taxes and homeowners insurance premiums as well. Both affect the overall affordability of a home. In New Jersey, for example, property taxes and insurance premiums combined average $7,270. You'd pay just $1,444 in, say, Kentucky, one of the 10 most tax-friendly states for retirees. Some state and local governments reduce or even waive property taxes for residents 65 and older.

Feeling adventurous? You might be able to pay even less for a home and enjoy lower living expenses if you retire overseas. Look into bargain-priced and retiree-welcoming countries such as Belize, Mexico, Panama and Vietnam.