Worrying about retirement is not confined to older generations, as even millennials say retirement savings is their biggest financial concern, according to a new study.

Saving enough money for a comfortable retirement is the most common financial stress inducer for people of all ages, according to a survey from Schwab Retirement Plan Services Inc. 

In the survey of 1,000 401(k) plan participants, 40 percent named saving for retirement as a significant source of financial stress, compared to 24 percent who said job security was top of their worry list, 21 percent who cited paying off credit card debt and 20 percent who named keeping up with monthly expenses.

Despite having more time to accumulate retirement savings, 38 percent of millennials named saving for retirement as a significant source of financial stress, even above paying off student loans, which was the top concern for 24 percent.

Almost half of the respondents feel it is impossible to save enough in their 401(k) for a comfortable retirement.

“With so many competing obligations and priorities, it’s natural for people to worry about whether they’re saving enough for retirement,” says Steve Anderson, president of Schwab Retirement Plan Services. “Roughly nine out of ten respondents told us they are relying mostly on themselves to finance retirement.”

A 401(k) is either the largest or only source of retirement savings for most respondents. Ninety percent call the 401(k) a must-have benefit and would think twice before accepting a job that didn’t offer one.

However, merely participating in a 401(k) plan is not enough. Only half of respondents feel totally on top of their 401(k) and slightly more than one-third is stressed about choosing the right 401(k) investments, Schwab says.

401(k) participants feel that having professional assistance may help improve their financial situations, with 70 percent saying they’d like personalized investment advice for their 401(k) plans.

“People who use 401(k) investment advice tend to save more, are better diversified and stay the course during market uncertainty,” says Catherine Golladay, senior vice president of participant services and administration at Schwab Retirement Plan Services. “Advice helps build confidence, too. Roughly three-quarters of the people we surveyed say they’d feel very or extremely confident making 401(k) decisions with the help of a financial professional. Only 44 percent would feel that same level of confidence on their own.”

The desire for help and guidance extends beyond 401(k) investing and retirement planning. Eighty-five percent say they would be interested in using a financial wellness program if it were offered by their employer.