When she was 22 years old, Erin viewed buying a family home as an exciting step for her and her husband, Jesse. Even though they didn’t necessarily plan on living in Wilmington, North Carolina, forever, buying a house seemed like a sound investment for a newly married couple.

Fast-forward ten years. Now in her early thirties, Erin’s perspective has completely changed. After the housing crisis of 2007, the couple opted to sell their home and return to renting.

“Now, we see owning a house as a burden,” she says. “It’s something that takes a lot of money to purchase, even more money to maintain, and then offers no assurance that you’ll be able to leave when you want to.”

Erin is one of an increasing number of millennials who are choosing to rent instead of buy. Homeownership rates among people age 35 and under have been on the decline, down by 21% from 2004. The pattern is clear, but the reasons range from financial concerns to alternative lifestyle choices.

Breaking the bank

Philip, a 32-year-old landlord with four rental properties on Cozy, thinks most fellow millennials want to buy, but they just can’t afford it.

“I think the stories saying millennials don’t want to buy are way off the mark,” he says. “Millennials can do basic math, and renting just doesn’t make sense long term.”

Younger renters name a variety of reasons for choosing to rent, but financial concerns are at the top of the list. According to the Pew Research Center, sixty-four percent of Americans say homeownership is simply not affordable for young adults in their 20s and 30s. Surveys also show that many millennials hope to own a home in the future, but see it as unattainable for now.

Millennials are still very interested in buying a house, but they’re delaying that decision, said Svenja Gudell, chief economist at Zillow, in the New York Post. Frequently, they’ll wait to buy a house until they start having kids.

Then there’s the reality of having to save for a down payment and qualify for a mortgage. These days, banks are much stricter about approving mortgages, and tightening credit standards have made it much harder to qualify for a home loan—and not just for millennials. According to the Urban Institute, tight credit standards are responsible for over 1 million failed mortgages in 2015.

A combination of higher down payments, lower wages, and stringent lending conditions have made it difficult for a number of young adults to save enough money to purchase a home. The Australian real estate mogul, Tim Gurner, offered millennials the now famous advice to stop buying avocado toast.

Overpriced lattes and avocado toast might be an extra expense, but student loan debt isn’t making it any easier. Forty-six percent of buyers 36-years-old and younger reported having some student loan debt. Being burdened with large student loan payments makes it even more challenging for young buyers to save.

“They can’t buy because of student debt and low wages,” Philip says. “I couldn’t buy until I got married and we pooled money. I’ve got $100k in student loans.”

Questioning the investment

Emily, a 30-year-old renter in San Diego, California, isn’t sure about making the investment. “I choose to rent because I fear long-term, substantial debt. In today’s market, job security is harder to come by,” she says. “Even if I got a low-rate mortgage, the idea of long-term debt isn’t something I’m comfortable taking on.”

“I know I’m not alone with this fear, especially during a time period when student loan debt is more than auto and credit card debt combined,” she continues.

Others aren’t so sure it’s an investment at all. Despite paying a higher rent than the mortgage on their former house, Erin and Jesse view renting as more financially beneficial.

“A lot of people say renting is a waste of money, and it’s true that our rent is probably more than a mortgage would be,” Erin says. “But factor in insurance, repairs, maintenance (roof repairs! air conditioner repairs! the toilet’s leaking!), upgrades, and all the other expenses that come with having a house, and for us, renting seems like a better value.”

Seeking freedom

Erin says that her family enjoys being mobile and not tied down to one place. For some millennials, putting down roots isn’t appealing, but scary because of its permanence.

Katelyn, a 23-year-old in Portland, Oregon, says it all comes down to one word: freedom. “I rent because it’s much less of a commitment,” she explains. “It gives you more opportunity to live in different places.”

She and her boyfriend Ryan have had the chance to live in the country and the city. They’ve also had the opportunity to travel. “Our last lease just ended, so we put all of our stuff in a garage and road-tripped around the country for 6 weeks,” she says.

Katelyn and her boyfriend are also one of many millennial couples that are waiting to get married—another potential cause for delayed homeownership. In an American Family survey, young people were significantly more likely than older respondents to live with a future spouse before settling down. Delayed marriage means many millennial couples opt to rent together as a “test” before making any long-term commitments—whether it’s getting married or purchasing a home.

Spanning generations

It isn’t just millennials choosing to rent. Overall, homeownership is at a record low, reaching the same number that it was in 1965: 63% of Americans. Potential buyers across many age groups are feeling the long-term impacts of the housing crisis.

Many older Americans are returning to renting after either losing their homes in the recession or making the decision, like Erin and Jesse did, to enjoy the perks of renting.

Erin explains that what once worked for a family may simply change over time. “Buying a house was super exciting…when it was new,” she says. “And then it wasn’t anymore, and we were stuck with this house that may have fit our needs at one point but no longer did.”