Get more from Social Security

Most seniors file for benefits as soon as they become eligible at age 62, even though that results in a permanent haircut in their monthly benefits.

Many seniors have no choice: They've been laid off or downsized, and companies aren't exactly lining up to hire older workers (or young ones, either). Others have been forced to file as soon as they're eligible because of health problems. Some have physically demanding jobs that eventually take their toll on aging bodies.

In 2008, nearly 73% of retirees claimed Social Security benefits before 65, and only 14% took benefits the month they reached full retirement age, according to a recent report by the federal Government Accountability Office. By taking benefits on or before their 63rd birthday, nearly half gave up 25% to 33% in additional monthly inflation-adjusted benefits that would have been available if they had waited until full retirement age, the GAO said.

Getting the most out of Social Security benefits has taken on added importance, because most retirees can no longer rely on a traditional pension to provide a lifetime source of income. And numerous studies have shown that most workers haven't saved enough in their 401(k) plans to make up for the loss of a traditional pension.

If you're 62 and out of work and need to pay the electric bill, filing for Social Security may be your only option. But for many retirees, Setzfand says, the decision to file for benefits is an emotional choice — they hate their jobs, for example, or just don't feel like working anymore.

On Monday, the AARP launched a Social Security Benefits Calculator that's designed to take some of the emotion out of this important decision. The interactive tool allows you to estimate how much you'll receive in monthly and lifetime benefits, based on your salary and your age when you file