NEW YORK  - The typical millennial tax client that accountant Jeffrey Gentner sees in Buffalo, New York is often dragged along by mom or dad to suffer through the process. 

Gentner had one such family in his office recently - a dad who brought in three sons, aged 25, 28 and 33. They just sat there while Gentner did all the returns. Then dad paid the bill and even wrote the check for the money the middle son owed to the state. 

"The kids don't ask any questions. I try to address them - sometimes it works and sometimes it doesn't," Gentner says. 

Taxes for young adults under 35 are not going away, and they are likely to get more complicated with age. 

A study released today by the financial site Nerdwallet.com finds that 80 percent of millennials have concerns about the tax filing process, mostly regarding making a mistake. Nevertheless, only 17 percent are likely to hire a professional, compared to the national average of 29 percent. 

This is a lesson that Phil Bergevin, a 28-year-old restaurant worker in Williamsburg, Brooklyn, learned over the past three years of doing his own taxes. Bergevin is still paying off the $1,000 he owed when his employer did not take out the correct withholding from his paychecks. 

RELATED: An accountant will do your taxes at this Brooklyn bar

This year, Bergevin is turning to his former roommate, CPA Shane Mason, also 28, to do his taxes. 

The clients that Mason sees are no slackers living at home, but are hustling day jobs and side gigs to make it in New York. 

To reach more millennials, Mason recently set up shop at a booth in a friend's bar in Bushwick, charging $135 and up per return. 

STUDENT LOAN INTEREST

Claiming student loan interest is a big issue for Mason's clients. 

"They bring me their documents and have no idea how it's going to affect them," Mason says. 

The interest amount is reported to the individual by their lender and needs to be inputted into the 1040 form. But there is a maximum amount of $2,500 in interest that can be claimed, and the income cap starts at $65,000. 

Some of Mason's clients, given the cost of living, make too much to qualify, and sometimes pay more in interest than the limit.  

HEALTH INSURANCE

Another issue that crops up is the penalty for not having health insurance. Many of Mason's freelance clients cannot afford plans on the state's marketplace and end up taking the $400 penalty. Others underestimate their income to get subsidies through the Affordable Care Act and owe money. 

"I don't have any sob stories about anyone losing a limb and not having health insurance, but people think they were going to get a small refund, and then all the sudden owe $100 because of the penalty," Mason says. 

RELATED: Recent college grads don't think their education was worth it

EDUCATION  CREDITS

]Sorting through  education  tax credits is complicated for both millennials and their parents and is the subject of many tomes (http://reut.rs/1LjFcZG). 

But the main concern for Vlad Lapochkin, an enrolled agent who prepares taxes in Las Vegas, is the number of IRS inquiries for proof of paid tuition and fees that come after the fact. 

The notices come with payment vouchers for people who have claimed a credit but might not have qualified for it, and his clients get frightened that they owe thousands of dollars. 

"Some just write a check and send it back," Lapochkin says, even though he can usually clear everything up by sending the required information. 

FUTURE PLANNING

When enrolled agent Manasa Nadig deals with millennial tax clients in Michigan, she takes the opportunity to try to talk about retirement planning. 

"I always find a little resistance, especially with the ones whose parents have helped them," Nadig says. "Start early and do it little by little."

Sometimes the lessons stick. 

Gentner was surprised by one of his Buffalo clients who used to come in with his parents. The first year the twenty something visited Gentner on his own, he ended up owing $1,800. His mistake? Mimicking his married colleagues and selecting too many exemptions on his withholding.

Four years later, Gentner's client is "making a ton of money," he says. "He has a rental property. He's saving for retirement. He followed everything I said. What a transition!"