This year, you don't have to file your state and federal income taxes until April 17.
Even with that deadline less than a month away, 58 percent of Americans have yet to file, according to data from savings app Twine.
If you wait until the last minute, you could run into headaches, expenses and other problems.
Here are some of them.
"A lot of people are blindsided by their tax bill," said Greg McBride, chief financial analyst at Bankrate.com.
If you wait too long to file your taxes, he said: "You're short-changing yourself on time."
The sooner you file, the sooner you'll know if and how much you owe the government. That knowledge can help you plan to save for the bill and reduce the likelihood that you'll need to take out a loan or use a credit card to cover it.
Tax returns in which someone uses a stolen Social Security number to file continues to be a problem. Try to get your return in before a thief pretending to be you does.
"People who are trying to scam the system are getting their fake returns in very early," said Martin Davidoff, a certified public accountant and tax attorney based in Dayton, New Jersey. "Getting it in earlier is a defense against identity theft."
If you wait until the final days (or hours) to work on your taxes, you might have to frantically hunt down 1099s or call a relative to ask the cost basis on stocks they gave you.
Instead, give yourself enough time to research what documents you'll need and to gather them.
Ideally, tax filers should step away from their returns upon completion, then reassess, said April Walker, lead manager for tax practice and ethics at the American Institute of Certified Public Accountants.
"It's human nature," Walker said. "It's easier to see blatant errors once you've put it down and look at it later."
Even technical issues like a computer failure (or realizing that your information is on a laptop you left at work) could increase your chances of making mistakes.
"If you run into a glitch at the last minute, there's just not enough time to remedy the situation which may result in your return getting filed late," Walker said.
If you're using a tax professional, expect them to be busy as that April 17 deadlines approaches.
"As things come in, we put them in a queue, first in first out," Davidoff said. "You'll get more attention from your tax preparer if you get it in in March than if you get it in in April."
In addition, rushing last's year filing could leave you less tax-informed about this year, said Brian Thompson, president of the National Society of Accountants. (This year there's even more to know, of course, thanks to the massive overhaul to the tax code).
"When I work with clients, I'm also planning with them for 2018," Thompson said. "It's the time of the year they're in our office."
If you need another incentive, remember: The sooner you file, the sooner that return will be in your back account.
"The longer you go without it," McBride said, "the longer you're giving the government an interest-free loan."