You can't predict how long you'll live. Nonetheless, you still need to consider longevity as a key factor in creating and following a long-term investment strategy.

Your projected lifespan may be longer than you thought. Men who turned 65 in 2010 can expect to live another 18.6 years, while women who reached 65 then can anticipate another 20.7 years, according to the 2011 Social Security Trustees Report.

These figures are averages. Depending on your health and family history of longevity, you could well spend two or three decades in retirement.

Possibly because people are now realizing they may have to support themselves far longer than earlier generations did, they seem to be growing increasingly worried about running out of money in their later years.

A poll of people 44-75 years old, sponsored by Allianz Life Insurance, showed 61 percent said they fear depleting their assets more than they fear dying.

If you're worried about outliving your resources or if you think you may become one of those people what steps should you take now and during your retirement?

Here are a few ideas:

Keep investing. Put away as much money as you can afford for your retirement. Take advantage of tax-deferred accounts such as your 401(k) and traditional IRA, or tax-free accounts, such as a Roth IRA. Roth IRA earnings are tax-free if you've had your account at least five years and you don't start taking withdrawals until you're at least 59. Keep investing, year in, year out, despite inevitable market volatility you'll encounter along the way.

Reassess your retirement age. If you enjoy your work, you might consider staying at your job a few years later than first intended. Those extra years of income, not to mention extra contributions to your 401(k) and potentially bigger Social Security payouts, can make a big difference to your retirement lifestyle.

Delay taking Social Security. As laws stand, you can start taking Social Security as young as 62, but your monthly checks will be bigger when you reach your "full" retirement age. You'll get your biggest monthly Social Security checks if you wait until age 70, when they "max out," but many people feel waiting that long may not be worth it when weighing lost years of any payments against the unknown variable of life expectancy.

Link:
How to cope with the ‘threat' of longevity