As companies continue to drop pensions that have afforded generations of workers a comfortable retirement, a chorus of financial experts warns that workers must learn to save for themselves.

But like admonitions to exercise more and eat less, many workers aren't heeding the advice. One recent survey revealed that one-fifth of Americans think their best shot at amassing savings of several hundred thousand dollars is to win the lottery. And that's far short of the $1 million that some financial planners say baby boomers will need for a nest egg.

"You can stop anyone and ask them if they should be saving more for retirement, and none will say no," said Christine Fahlund, senior financial planner with T. Rowe Price Group Inc. "We've heard it and heard it and heard it. It's our own fault if we ignore it. We have to live with the consequences."

The announcement recently that International Business Machines Corp. plans to freeze pension benefits and put workers into a 401(k) plan was seen by many retirement experts as pivotal in the shift away from corporate pensions. Those benefit plans first became popular after gaining tax exemptions in the early part of the 20th century and defined retirement security for the post-war generations. As analysts predicted that an increasing number of employers would follow the blue-chip company's lead, the headlines fueled anxiety about retirement safety nets — the same fears that helped derail President Bush's attempt to create private savings accounts under Social Security.

Over the last quarter-century, the percentage of private-sector workers who rely on defined-benefit plans or pensions has shrunk to 6 percent, while the percentage of workers in defined-contribution plans such as the 401(k) more than quadrupled to nearly 30 percent.

The shift puts more responsibility on workers' shoulders, exacerbating concerns that Americans in general don't save enough and aren't savvy enough to navigate the financial markets on their own. And companies, some of which shed pension plans because they could no longer afford them, have come under pressure to ensure that employees become better stewards of their own retirement.

The problem with the 401(k) is that people don't contribute enough. According to Federal Reserve data, U.S. households led by people 55 and 64 years old have a median of $55,000 in retirement accounts, including 401(k)s. For those who are 65 and older, about 20 percent of them count Social Security as their only income, according to the Social Security Administration.

Olivia Mitchell, director of the Pension Research Council at the University of Pennsylvania's Wharton School of Business, said people underestimate what they will need in retirement, especially as people live longer. "Lump-sum delusion," she calls it.

"They think, 'Oh golly, I've got $100,000 in my 401(k), I'm rich,' but they don't realize that's just not very much money spread over 20 years," Mitchell said.

As for what people should save, T. Rowe Price crunched the numbers with a computer simulation that's able to account for thousands of possible market scenarios.

The conclusion: Individuals should save at least 15 percent of pretax salary in order for those investments to bring half of that salary in retirement.