I am an inveterate duplicate bridge player, and in the Aiken Bridge Club, we have two 90-year-old individuals who play bridge each week, quite competitively I might add. Playing bridge regularly has been shown to have a positive impact on longevity.

Actually, only 5 percent of 65-year-old females and 3 percent of males will live to age 100, according to the actuaries at the Social Security Administration, but 29 percent of males and 39 percent of the ladies will live to 90. This is the good news.

The bad news is that living so long can reduce or even wipe out your retirement assets, so it is vitally important to plan for the possibility that you will live longer than you might have imagined.

According to Mark Miller, 40 percent of adults underestimate their life expectancy by five or more years.

So then, the first step in managing your retirement assets is to assess the likelihood of your living to age 85, 90 or even longer.

The most important longevity factors are (1) your family history; (2) your current health status; (3) your lifestyle choices; and (4) wearing a seat belt.

In addition, regular exercise, a positive outlook, recurring social interaction and diet are important contributors, as well.

According to author Christine Benz, here are four mistakes to avoid in managing your retirement assets for the long term.

The first mistake is to overemphasize conservative investments. In my financial planning practice, I have encountered more than a few persons whose entire retirement portfolio is in certificates of deposit and bond-based funds.

The problem with holding lower interest-bearing bonds is that in the event that future interest rates go up (even slightly); those bond values will go down.

Being overweighted in bonds and cash could mean that one's returns will not even outperform the inflation rate.

The answer is to have a mix of investments with a greater emphasis on equity-based investments, particularly if your parents lived beyond 85 or 90 and your current health is good.

Believe it or not, 50 percent in equity based funds may not be too much. My personal allocation at age 70 is 50 percent in fixed investments, and 50 percent in equities, and all of these assets are in tax deferred accounts.

As a result, I take my RMDs from the fixed side of the house and leave the equity side alone. I have projected that my fixed investments will be enough to provide 5 to 6 years of future income, and in that time, I should have sufficient time to recover from any downturn in the equities market, foreign and domestic.

The second mistake is taking your Social Security benefits too soon. Don't forget that these payments are inflation adjusted, so by delaying the commencement of your income stream, you are increasing your income by 8 percent for each year that you delay receipt beyond your social security normal retirement age.

The compounding effect of applying the inflation adjustment to a 32 percent greater monthly income at age 70 will be huge if you live to age 85 or longer.

If your family history is not great and your health status could be better, by all means take Social Security when you are eligible for full benefits.

The third mistake is in simply withdrawing too much money in the early years from your retirement accounts.

The “4 percent adjusted for inflation” rule may be too much early on, if you expect to live longer. This is particularly true if you assets are overly weighted on the conservative side.

The other misstep is to not consider the only investment that guarantees income – a fixed annuity – for at least part of your retirement assets.

I like deferred income annuities for a portion of your portfolio which will provide an income stream that can commence when you actually reach 80 or 85.

Not all annuities are equal, so check with a knowledgeable professional.

Greg Roberts is a certified financial planner with 35 years of financial and estate planning experience. Got a financial planning question for Greg? You may email him at greg@lifesolutionsonline.net.