WASHINGTON -- Malcolm Buckey would be 97 years old when the 30-year mortgage on his dream home in Ponte Vedra Beach, Fla., is paid up.

Walter Molony of Annandale, Va., would be 84 when the last payment comes due on his 30-year loan.

For many middle-age homeowners, taking advantage of low mortgage rates will have an unintended consequence: As retirees living on reduced incomes, they will still have mortgages to contend with.

Experts say these people should carefully think through their financial game plan when opting to take out a 30-year loan rather than a 10-year or 15-year loan to finance a new home or refinance the home they already own.

"You could have a significant financial problem if things don't go as planned," said Mark Zandi, chief economist at Economy.com.

"For instance, your income isn't as strong as you thought it would be and you won't be able to pay off your mortgage as quickly as you had thought. Or, home prices end up being a lot weaker than you expected, and you won't be able to sell and pay off the mortgage," he said.

People of average financial means probably should try to avoid being saddled with mortgage payments when they are retired, financial experts said. Nonetheless, it can make financial sense to take out a longer-term 30-year loan now, they added.

In general, people in their 40s and 50s are enjoying their peak earnings years, experts said. While that can make people better able to handle a shorter-term mortgage, a longer-term one may offer more financial flexibility.

After selling a home in Richmond, Va., Buckey said he had the cash to pay for his ranch-style home in Florida. He decided to finance about 20 percent of the new house with a 30-year loan because the lower monthly payments offered flexibility, and he also would get a tax break. "It was a budgeting issue," he said. "We wanted to make improvements."

Extra money for such projects or for retirement investments, and the accompanying tax benefits, are among reasons people cite when going for 30-year mortgages.

Molony, 54, refinanced his home mortgage twice this year and each time went with a 30-year loan.

In March, he and wife, Cathy, took out a larger loan and used the extra cash to make extensive repairs and upgrades on their house in Annandale, Va., and to pay off the mortgage on a cabin in the mountains of West Virginia. In June, he refinanced again to lower the monthly payments even more.

There is a tax break to consider, said Greg McBride, a financial analyst with Bankrate.com, an online financial service. "By taking out a 30-year mortgage, you are paying down a lot less principal in the longer term, getting a larger tax deduction through the interest you are paying," McBride said.

Experts say people in their 40s, 50s and older who take out 30-year loans probably will pay them off ahead of time. They may be banking on a sharp rise in the value of the home, which then could be sold well before the 30-year loan is finished and the loan paid off to leave a tidy profit. Or they may be expecting a huge bonus or some other cash windfall that could be used to pay off the loan early.

Buckey said he plans to pay an additional amount to the principal each month. "It could be 20 years when I'm done," he said.

"It is not a valid assumption to believe that everyone who took out a 30-year mortgage will pay it off in 30 years," said Doug Duncan, chief economist at the Mortgage Bankers Association of America. "The average life of a 30-year mortgage now is probably 7 or 8 years," he said. That means it is paid off in that period, either through refinancing or early repayment.

That trend has been heightened in recent years as millions of homeowners have moved to refinance their home mortgages to avail of the lowest mortgage rates seen in four decades.

In the middle of June, rates on benchmark 30-year mortgages slid to 5.21 percent, a record. Shortly after that, rates started rising, but have gone down again in the past several weeks.

Sally Hurme of AARP, who deals with consumer protection, advises people to ask themselves some of these questions: How would I make the payments if I were no longer working? What expectations do I have about appreciation of the property? Is this the place where I think I will live for the life of the loan? How much debt am I going to be able to manage should my income be reduced?

She said that when people refinance and take out loans larger than they need to finance a house, they ought to think carefully about what they are going to do with the extra cash -- for example, debt consolidation, paying for children's tuition, taking a trip around the world.

Some experts believe that the baby boom generation is less worried about taking mortgage debt into retirement than their parents' generation.

"Preserving my home to leave to my kids. The sort of joy and sense of personal accomplishment to have paid off my mortgage and be able to leave my house free to my kids is one of those ingrained personal finance philosophies we know of the older generation," Hurme said. "I think that boomers are not as debt-averse as their parents."