Working longer

The retirement-plan industry regularly extols the virtues of 401(k)s and other retirement investment programs. Yet a survey of the heads of many big employer retirement plans found that nearly 80 percent of them agreed that "the days of working until the age of 65, retiring, and then never having to work again are generally over for most workers."

Traditional pensions are struggling for many reasons: low investment returns, too-generous benefits, and the happy fact that people are living longer than expected.

More than half of U.S. workers have no retirement plan at all. And even those who do have a 401(k) typically don't have enough money to retire comfortably

When lawmakers added a subsection to the tax code called the 401(k) more than three decades ago, they could not have imagined that this string of three numbers and a letter would become a fixture in the financial lexicon.