Americans added $28.9 billion to their outstanding credit balances in September — the largest one-month jump since the U.S. entered World War II, lifting total consumer borrowing to a record $3.5 trillion, according to the Federal Reserve.

The increase, including a $6.7 billion rise in credit card borrowing, shows that Americans are taking on more debt after a long stretch of paying down their loan balances in the wake of the Great Recession.

That’s a sign that consumers are comfortable enough with the economy and the job market to spend again. A new survey from Merrill Lynch what Americans with $50,000 to $250,000 in investable assets are willing to go into debt for.

The survey found that most Americans have fallen short of their retirement savings or debt reduction goals for 2015 — and that 84 percent of respondents said they wouldn’t be comfortable making a big purchase today. If they are going to take on more debt, they feel justified in doing so for certain types of investments, especially for education or homes for themselves or their kids.

Many people also find that certain large purchases are justified if they endure (57 percent), have more value in the future (42 percent) or create lasting memories (27 percent). Millennials in particular are more likely than older generations to defend big expenses if they create lasting memories (61 percent vs. 21 percent) or feel like a “once in a lifetime” opportunity (55 percent vs. 28 percent).

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More than 40 percent of people would finance a purchase they couldn’t afford by either taking out a loan or charging the expense to their credit card, yet this choice usually comes back to bite people. Just over 30 percent regret not paying off debt faster in the last five years and 22 percent wish they had never gone into debt in the first place.

Although many Americans believe weddings are worth going into debt for and one third choose to do so, a couple might want to reconsider before charging extra expenses to their credit cards. If a couple carries $10,000 in credit card debt, with the average credit card rate of 15.76 percent, it will take them 12.5 years with a monthly payment of $400 to pay it off. In the end, they will have paid $14,787 – almost 50 percent more than the amount they originally charged.