(TNND) — Close to a third of Americans have made purchases with a buy now, pay later service. And close to half have reported problems including overspending, missing payments and regretting their purchases, according to a new Bankrate survey.

“I think the best way to use buy now, pay later is to isolate a single large purchase, hopefully something necessary,” Bankrate senior industry analyst Ted Rossman said. “I can see the business case for that.”

BNPL might work to even out cash flow and allow someone to get a new refrigerator or set of tires on a payment plan with low or no interest.

But Rossman said BNPL transactions can become very fragmented. And buyers can quickly overspend if they’re stacking purchases of $20 here and $50 there without adequately keeping track.

“There are some warning signs,” he said.

Bankrate found that PayPal’s Pay in 4/Pay Later, Affirm, Afterpay and Klarna were the most widely used services.

Forty-nine percent of BNPL users told Bankrate that they’ve experienced at least one related problem.

Nearly a quarter of users said they spent more than they should have.

Sixteen percent of users said they’ve missed a payment.

Similar shares said they regretted a BNPL purchase, had difficulty returning a BNPL purchase, or were dissatisfied with at least one BNPL purchase or experience.

Gen Zers were the most likely to have encountered issues. Two-thirds of those users ages 18-28 told Bankrate they’ve experienced at least one problem, such as missed payments, related to the service.

The most common reason people gave for using BNPL was to spread their cash flow, followed by taking advantage of low or no interest, and knowing what they’ll owe and how long it’ll take them to pay it off.

BNPL has really grown in popularity over the last five years, Rossman said.

It’s often integrated at the point of sale on e-commerce sites, offered as a payment option.

But Affirm, Afterpay and Klarna all have physical payment cards now that can be used at the gas station, grocery store or other places people shop in person, Rossman said.

And some installment plans are lasting longer and charging interest now, Rossman said.

“This buy now, pay later industry that's really portrayed itself as the kinder, gentler credit card is now behaving more credit card-like, which I find very interesting,” Rossman said.

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Klarna and DoorDash announced a partnership recently, which Rossman said some folks are “viewing as kind of a sign of the payments apocalypse.”

The idea of splitting a $20 fast-food order into payment installments “makes some people, myself included, kind of nervous,” he said.

Rossman said BNPL can be a valuable way to spread out your cash flow.

But he warned against using it as a crutch to spend too much or make impulse purchases.

“Sometimes you're better off waiting until you could actually pay for the item up front,” Rossman said. “So, you do need to know yourself and think about that total cost of ownership.”