When it comes to their finances, most Americans are filled with regret.

Fully three in four Americans say they have financial regrets, according to a survey of more than 1,000 adults published Tuesday by Bankrate.com.

Their biggest regret: Not saving for retirement early enough (nearly one in five Americans put this in the No. 1 spot). What’s more, among those 65 and up, 27% said this was the biggest regret, compared to 17% of those aged 30 to 49.

America’s biggest financial regrets

Percentage who say this is their most significant financial regret

• 18% Not saving for retirement early enough

• 13% Not saving enough for emergency expenses

• 9% Taking on too much student loan debt

• 9% Taking on too much credit card debt

• 8% Not saving enough for your children’s education

• 3% Buying a bigger house than you could afford

Indeed, it is costly to wait: A person who starts saving $300 a month for retirement at age 25 (assuming a 5% return on investment) will have about $450,000 saved by age 65, despite only contributing $144,000 into his retirement account. Meanwhile, if that person waits until 35 to save the same amount each month, he will contribute a total of $108,000 towards retirement but only have about $250,000 saved at age 65. “If you don’t start saving early enough, you will start to notice that later,” says Greg McBride, the chief financial analyst for Bankrate.com.

What’s more, waiting to save only exacerbates the problem of our already paltry nest eggs: According to 2015 data from the Employee Benefit Research Institute, fully 28% of workers say they have less than $1,000 saved and 17% have between $1,000 and $9,999; meanwhile, just 14% of workers have $250,000 or more saved.

That’s far too little, according to many financial advisers: Guidelines from Fidelity, for example, say that by the age of 30, you should have your entire salary saved; by 40, three times your salary saved and by 50, six times your salary saved.

Other financial regrets that Americans have include not having enough saved for emergencies (13%) and taking on too much student loan debt. Indeed, fully 62% of Americans have no emergency savings, according to a survey released last year by Bankrate.com; experts recommend that you have at least three months of living expenses in savings for emergencies. Furthermore, the amount of debt that students graduate with has risen rapidly: In 1993, it was less than $10,000 per student, in 2012, it was nearly $30,000, according to the Institute for College Access & Success.