It’s a scene all too familiar in American households: Debt piling up, with no end in sight.

Household debt is soaring. It grew in the fourth quarter of 2017 at the fastest rate since the fourth quarter of 2007 before the financial crisis, in large part because of a boom in auto sales, according to the Federal Reserve.

Americans collectively owe $13.15 trillion, including $9.33 trillion in housing debt and $3.82 trillion in non-housing debt, including credit cards and auto loans, according to the New York Federal Reserve. Household incomes are also rising, so the ratio of households’ liabilities to income is relatively low.

Behavioral economists have a few rules of thumb:

The $3.82 trillion question: repay by interest rate or loan?

Researchers have some conflicting thoughts about whether consumers should pay off their highest-interest debt first — seemingly, the most logical decision — or eliminate smaller amounts of debt in their entirety, known as the “snowball method.”

The snowball method can be more motivating, according to an experiment at the University of Michigan in 2011. Others say it makes sense to pay off the debt with the largest interest rate. This debate can create anxiety and a mental roadblock for people.

The most important step is to avoid procrastination, said Dean Karlan, an economics professor at Northwestern University who researches debt. After all, did you have a great debate when you were spending the money? Debit or credit? Cash or crypto? Check or PayPal PYPL, +4.05% ?

“You’re never tempted to pay off debt,” he said. “You’re tempted to spend money, and you’re going to have to deal with that.”

Whatever you do, don’t leave your repayments to chance

Set up an automatic transfer, said Emory Nelms, a senior researcher at the Center for Advanced Hindsight, a behavioral economics lab at Duke University.

Research has shown that cutting out an entire spending category, like eliminating eating outside the home entirely, or a pledge to buy zero new clothes, is more effective than trying to lessen spending in various categories.

Promising you’ll do fewer extravagant things, like “I’ll go out to dinner less this month,” doesn’t work so well, Nelms said. When it comes to cutting out bad habits, it’s all or nothing.

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Peer pressure gets people into debt — and out of it

Peer pressure can be an effective way to stay on track when paying down debt, Karlan said, especially if it this kind of pressure that led to the spending in the first place.

Ask a trusted friend, parent, sibling or even neighbor to help. “You can tell them, ‘I’m going to get a bonus, and I’m telling you now so that I stick to the goal of using it to pay my debt,’” he said. “Making those types of commitments can go a long way.”

Numerous studies have shown that an accountability partner or group can help achieve other types of goals. One Harvard working paper from 2017 showed peer pressure was the most effective way to make sure a hospital staff maintained the best hygiene practices possible.

Simply telling others “I’m working on paying off my debt” will usually elicit positive feedback. That can make you feel good, but that nice reward could actually stop you from following through, Nelms said. “You’re halfway convincing yourself you’re there.”