The cost of getting your taxes done can be very high, especially if you're paying the tax preparer an hourly fee.

According to a survey published in 2017 by the National Society of Accountants, tax professionals charge as much as $145 per hour to do taxes. At that rate, you'll probably want to use the time spent with one as efficiently as possible. 

Here are some tips.

Get Organized

Keep a close eye on the mail, and separate any envelopes with the words “tax information” or “tax documents.” Before visiting the tax preparer, sort the contents by category. If you have several income documents, group them into subcategories: W-2s and 1099s, for instance.

Even if you're paying a flat fee rather than an hourly fee, there's a benefit to doing a little legwork yourself.

More on Taxes

"Organizing tax documents can make the tax preparation process go more smoothly," says Gil Charney, director of The Tax Institute at H&R Block, the tax-preparation company based in Kansas City, Mo.

Ask your preparer for a tax-organizer worksheet or checklist—that is, a paper or electronic document to fill out in advance. If he or she doesn't have one, there's a free checklist that could be helpful at MyOnlineTaxAccountant. H&R Block also offers a free tax-prep checklist.

Keep in mind that gathering your tax documents and filling out the organizer might take a couple of hours the first time you do it. Once you've been with a preparer for a while, that onerous task should be faster.

You may also find that you're missing certain items, such as IRS Form 1099-DIV, reporting dividend income from an investment house. They sometimes arrive later in the tax season than your W-2 forms.

But that shouldn't stop a tax preparer from getting started if you have most of your documents, especially if your tax situation hasn't changed much from last year. Also, take along last year's tax return and supporting documents. They could be useful to your tax preparer.

Your First Meeting With a New Preparer

If you'll be using a new tax professional this year, expect to take many more documents to your first appointment. He or she will need them to get a handle on what you've earned and paid in taxes in the past. 

Eric Bronnenkant, a certified public accountant and head of the tax department at Betterment, a New York-based online investment company, recommends bringing the last three years' worth of tax returns. Provide supporting worksheets for those three years, too, if you have them.

Your tax history is particularly important if you reported investment losses in prior years. You may be able carry over and claim a portion of those losses on subsequent returns.

"It's common to lose carryovers when switching accountants," Bronnenkant says. "This potentially creates a situation where you could pay substantially more in taxes." 

Documents Not to Forget

Tax experts say clients often forget to supply a number of documents, delaying the time it takes to complete the tax forms. You can speed things up by reviewing the list of documents below and, if they apply, taking them with you.

  • Supporting documents for an after-tax IRA contribution to a traditional IRA. If you don't report the contribution using IRS Form 8606, you could end up paying double tax when you eventually take a distribution, says Bronnenkant. That's because the IRS will assume, incorrectly, that you didn't pay tax on the original contribution and will expect you to pay that tax when you take a distribution. (Done correctly, an after-tax IRA contribution is taxed only on the earnings, not on the original contribution.)
  • The closing letter for a home-mortgage refinance.
  • Real-estate tax receipts if you don't pay those taxes through escrow.
  • The taxpayer-ID numbers, addresses, and phone numbers of child-care providers.
  • Business mileage for your unreimbursed employee business expenses. (For 2017, it was 53.5 cents per mile.)
  • Proof that you've paid estimated quarterly tax payments. Without it, you could end up paying the same tax twice, Bronnenkant says.
  • Proof from any charity where you made a qualified charitable distribution directly to your IRA. (People age 70 1⁄2 and older can contribute up to $100,000 directly from an IRA to a charity and shave that amount off their taxable income. "If the taxpayer doesn't provide this information to their accountant, the accountant will treat the distribution as taxable," Bronnenkant warns.

If by late February you don't have all of the documents you need, follow up with employers, investment companies, or any others that may have generated taxable income.

"Not doing so can lead to missing out on tax benefits," Charney says. "Perhaps worse, forgetting to report income could invite an IRS inquiry."