It’s an annual tradition: As April 15 draws near, millions of Americans scramble to round up all their receipts and other documents from the previous year to make the federal tax filing deadline.
But that urgency can lead to poor decisions that cost thousands of dollars in the long run, tax specialists say.
NerdWallet surveyed certified public accountants and asked them to list the most common mistakes taxpayers make at tax time, as well as how to avoid them. Here’s what they said:

Mistake No. 1: Not Being Organized

Lugging a shoebox full of receipts into your tax preparer’s office may not be the best way to deal with your return, but at least those harried taxpayers have everything in one place. That’s not the case with many people, CPAs say.
“One of the biggest mistakes we see folks make is simply not being organized,” says New York-based CPA Becky Egan. “People constantly come in for their tax appointment without all their documents, forgetting their charitable contributions, neglecting to let us know they invested in a partnership, or leaving out a 1099 they received.”
Egan advises clients to keep track of their earnings, expenses, accounts and other important information during the tax year itself, instead of leaving everything for the night before their tax appointment.
“It’s impossible to do any tax planning if you’re always in reactive mode, looking behind at the year that’s passed.”
As Brian S. Devers, a CPA in Forest, Virginia, puts it: “January 31, when you receive your W-2, is not the time to do tax planning for the previous year, because that ship has sailed.”

Mistake No. 2: Not Getting Good Advice

Younger people with few financial complications can get by with filing a 1040EZ form, and tax-preparation software has turned millions of Americans into virtual tax experts. But for many people, filing taxes without getting professional help can be a costly mistake.
“The biggest mistake people make is that they prepare their own return or they go to a tax-prep shop that is not staffed with professionals,” says Huntington Beach, California, CPA Mark Prendergast. “While going to a CPA or an enrolled agent may cost more for the services, they are much more aware of tax savings techniques compared to the nationally syndicated tax-prep companies who hire and train part-timers.”
Prendergast says a tax professional can pick up on nuances that can save taxpayers plenty of cash. Knowing how to handle college tuition payments is one example. Qualified tax pros can figure out whether to use the tuition deduction, the American Opportunity Credit or the Lifetime Learning Credit to maximize tax savings.
“Determining which is the best [option] can save hundreds, if not thousands, of dollars,” Prendergast says. “Some apply to some situations but not others. Maybe one dependent child qualifies for one, but another child qualifies for another.”
Another key decision for which good advice is needed is whether to make a Roth IRA contribution or a traditional IRA contribution, he says. “Usually [people] think, ‘I save taxes with a traditional IRA but not with a Roth IRA.’ But in certain circumstances, a Roth IRA contribution will give rise to the Retirement Savings Contribution Credit (Form 8880) and save the person some taxes.”

Mistake No. 3: Not Contributing to an IRA

This issue leads to the third major mistake that CPAs cite.
“The biggest mistake people make at tax time is not contributing to an IRA because they are not eligible for an income tax deduction on the contribution amount,” says San Francisco-based CPA James Dowd. “Every taxpayer under the age of 70½ with earned income is eligible to make an IRA contribution. If the taxpayer has no existing IRA, the mistake is especially costly, and it compounds over time, because they could make an after-tax contribution and immediately convert the IRA to a Roth with no tax consequence.”
For a 30-year-old taxpayer, Dowd says, the cost of this mistake “could easily be worth more than $250,000 over a lifetime.”

Zoran Basich is a staff writer covering personal finance for NerdWallet. Follow him on Twitter@zoranbasich and on Google+.
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