How to Handle the Financial Consequences of Millennials Living at Home

— -- Marisa Pyatt sleeps in the same bed she did when she was 10 years old -- even though she’s 24 now.

Pyatt isn’t alone. According to a May report from the Pew Research Center, living with parents is now the most common arrangement for millennials -– the term used to refer to adults currently between the ages of 18 and 34.

Marisa's parents, Vicky and Bob Pyatt, work three jobs between them. They allow their daughter to live in their Indianapolis home rent-free while she pays off her student loan debt.

"[It] kind of makes me, mad when I look at all my loans,” Marisa said.

Added her mother: “I don't really make her give me money for every little thing like I should do.”

ABC News talked to Peter Dunn, a personal finance expert, about how millennials and their parents should handle the arrangement.

Dunn, who has written about this topic for USA Today, said it’s essential that young adults have a plan to leave home.

“The bottom line is - your financial problems should not become anyone else's financial problem,” he said.

Pyatt graduated more than one year ago from Indiana University with a bachelor's degree in human development and family studies.

She says she makes $2,000 per month at her full-time job with Big Brothers Big Sisters. She has about $57,000 in loans and pays about $700 on the debt.

Dunn had some practical advice for Pyatt and her parents -– and other families who find themselves in similar situations.

He suggested they create a budget and figure out where they were spending their money. When Bob and Vicky did that, they figured out that they were spending an extra $300 to $400 per month on their daughter’s expenses, such as her car payment, cellphone bill and loans. Those costs were eating away at their own savings.

“The difference of putting that money away now … until the day you retire would be a $176,000 difference,” he told the couple, adding, “Bob, you're going to be working deep into your seventies."

“I don't want to work until I'm 70 or 80 or just fall down dead,” Bob said.

With Dunn's help, Marisa learned that she actually makes enough money to live on her own -– if she spends wisely.

Dunn gave her two options: Save $800 a month for three months in order to prove to herself that she can live on her own, or start paying rent to her parents immediately.

“That will get you out sooner rather than later ... and ultimately gives some of their retirement back,” Dunn said.

Marisa decided to save the money instead of paying rent.