The concept of a retirement age is going the way of the typewriter, another 20th century relic that has been made irrelevant by changing circumstances. Many middle-class Americans now expect to work until they have saved enough to afford to retire, according to results from the seventh annual retirement survey from Wells Fargo & Co.

Three-fourths of the 1,500 middle-class Americans surveyed by telephone by Harris Interactive in August and September 2011 say it is more important to have a specific amount saved before retirement, regardless of age, while only 20 percent say it is more important to retire at a specific age, regardless of savings.

The survey also found that a quarter of middle-class Americans say they will "need to work until at least age 80" to live comfortably in retirement.

Three-fourths of those surveyed expect to work in their retirement years, including 39 percent of all respondents who say they will need to work to make ends meet or maintain their lifestyles, while 35 percent say they will work because they want to, rather than out of financial need.

Among middle-class Americans age 40 to 59, 54 percent say they will "need to work," compared with 34 percent of those age 25 to 39.Accordingly, only 25 percent of those between the ages of 40 and 59 say they will work in retirement because they want to, versus 45 percent of Americans between the ages of 25 and 39.

Of those surveyed who say they will work in retirement, 47 percent say they will do similar work to their pre-retired years, while 42 percent say they will work in a position that requires less responsibility.

"The fact that the vast majority of middle-class Americans expect to work well past the traditional retirement age has significant societal and economic implications," says Joe Ready, director of Wells Fargo Institutional Retirement and Trust. "Will people be physically and mentally able to work later in life? What will it mean for young people entering the work force? And how does our system of retirement savings need to be reformed to help reduce the savings gap?"

Since at least the early part of the 20th century, Americans expected to work until hitting a retirement age—often 65—and then to retire with an employer-paid pension plan. However, defined-benefit pensions are now uncommon in the private sector and are being scaled back for a growing number of new government employers. At the same time, political leaders are discussing cuts to future Social Security and Medicare benefits, and many Americans have seen their savings washed away by unemployment, sharp declines in house values, and wild swings in stock prices.

As political leaders consider potential cuts to future Social Security and Medicare benefits to help close the budget gap, 49 percent of those surveyed between the ages of 25 and 49 are willing to accept future cuts to help reduce America's debt burden. Only 28 percent of those age 50 to 59 and 19 percent of those age 60 to 75 would be willing to accept cuts.

"We've seen a shift in the role of work and employment during the traditional retirement years, but we're also seeing a shift in expectations for social support," says Laurie Nordquist, director of Wells Fargo Institutional Retirement and Trust. "There is a willingness among younger Americans to put traditional support systems on the table for reform as we look for solutions to strengthen the country and address the debt load of our nation."

On the question of willingness to consider Social Security and Medicare cuts, the divide between those younger than 50 and those older than 50 may be linked to the fact that younger people aren't counting much on Social Security anyway. More than a quarter of people surveyed in their 20s (26 percent) and 30s (28 percent) expect no income at all from Social Security during retirement years, and on average, people of those ages expect Social Security to cover only 20 percent of their retirement funding.

By contrast, those in their 50s expect Social Security to provide 36 percent of their retirement funding, while those in their 60s expect it to cover 46 percent. Democrats surveyed expect a higher percentage of their monthly retirement income to come from Social Security (30 percent), compared with 25 percent for independents and 24 percent for Republicans. But in willingness to consider benefit cuts, responses from Democrats and Republicans were within the sampling error: 48 percent of Republicans and 44 percent of Democrats were willing, compared with only 41 percent of independents.

This willingness increased with household income: While only 39 percent of those earning between $25,000 and $49,999 were willing to take a reduction, a majority (55 percent) of those earning more than $100,000 were willing to do so.

A majority of middle-class Americans (53 percent) surveyed say they need to cut back significantly on spending today to save for retirement. Americans have saved, on average, only 7 percent of their desired retirement nest egg—a median of $25,000 in retirement savings compared with a median retirement goal of $350,000. Three in ten people in their 60s have saved less than $25,000 for retirement, possibly indicating they will rely heavily on Social Security.

"For several years now, we've seen that Americans are undersaving for retirement, and a majority do not trust the stock market as a place to invest for retirement. However, we did find a bright spot among middle-class Americans; more than three quarters do not want to retire with mortgage debt. This is an important goal, particularly for younger Americans," Nordquist says.

After experiencing the home mortgage crisis of the past several years, people have taken to heart the idea of retiring without mortgage debt. Four-fifths of respondents ages 25 to 75 say it is important to own their home debt free by retirement, and 63 percent of respondents say they wouldn't consider being renters in retirement. Older generations seem less concerned about retiring without mortgage debt. While 87 percent of those age 25 to 29 say it is very important to pay off mortgage debt, only 40 percent of those ages 60 to 75 agreed.

Confidence in the stock market remains low, with 68 percent saying they aren't confident the stock market is a good place to invest for retirement. When Americans were asked what they would do to invest $5,000 for retirement—invest in a CD or the stock market—50 percent of respondents said "invest in mutual fund or stocks," and 45 percent said they would purchase a bank CD. The percentages flipped when people age 25 to 29 were asked the question.

A plurality of those surveyed say being able to pay monthly bills is their most important day-to-day financial concern, ahead of health care, education, and saving for retirement.

Even those between the ages of 60 to 75 say paying monthly bills is a bigger concern than health care costs.

In fact, middle-class Americans are significantly underestimating the amount of out-of-pocket health care costs they will face in retirement. Respondents estimated a median of $60,000 in costs, while only 20 percent estimated $100,000 or more. A 2010 study from the Center for Retirement Research at Boston College estimated that the present value of lifetime uninsured health care costs for a typical married couple age 65 will be $197,000.

Economists have long talked about the massive amount of wealth that will transfer between generations as the baby boomers age. But among the middle class, shifting economic realities mean those transfers will often disappoint.

Four in 10 middle-class Americans expect to leave no inheritance to their children due to money needed to support their own retirement. Even among those surveyed who have more than $100,000 in household income, three in 10 people expect to leave no savings behind.

If they had enough money to spend in retirement, nearly three-fourths of middle-class Americans surveyed say it is more important to have money to enjoy experiences now with their children or grandchildren, compared with 22 percent who would rather save the money to pass on later to their heirs.

Enjoying life now and not worrying about retirement is inversely related to household income; those with higher household incomes are more worried about retirement. While 57percent of those earning less than $25,000 annually agree that "I plan to enjoy life now and I'm not worried about retirement/tomorrow," only 26 percent of those earning $100,000 or more share that sentiment.