NEW YORK — Procrastinators, start your engines. Or at least, fire up your laptops. There's less than a week to go before you must file your 2008 tax return.

Just over 92 million returns were filed with the Internal Revenue Service through April 3, about two-thirds of the 141.2 million expected this year.

The total is expected to be about 10 percent below last year's, when many people who weren't required to file sent in returns so they could claim economic stimulus checks. But even with the reduced expectations, there's still plenty of people who have put off the task.

Both the number of refunds and the average refund size are up so far this season. The IRS says it has sent out almost 78 million refunds so far, up 3.4 percent from a year ago. The average refund jumped 11 percent, to $2,705.

Of course, many people wait until the last minute to file because they owe taxes, or suspect they do, while those expecting a refund tend to file early. So the influx of last-minute returns is likely to push the refund rate and average amount down slightly.

If you haven't sent in your return yet, here are some things to keep in mind:

Deductions. Before automatically taking the standard deduction, try this quick test suggested by Bob Scharin, senior tax analyst at Thomson Reuters' Tax & Accounting business, to see if you're better off itemizing. Add up your mortgage interest, real estate taxes and the amount of state and local tax withheld listed on your W-2.

If your total comes to more than the standard deduction, you'll benefit from itemizing.

Tax credits. If your income declined last year, you might be eligible for tax credits you couldn't claim in the past. The earned income tax credit, childcare credit and the Hope and Lifetime Learning education credits are all income-based. Unlike itemized deductions, credits are subtracted from your tax liability dollar for dollar.

Medical costs. Be aware that medical costs that equal 7.5 percent or more of your adjusted gross income are deductible. If you had a major medical expense last year, or several smaller ones, it's worth adding up your receipts to see if they meet the threshold.

Investments. If you're planning to claim investment losses, make sure you know their basis, or the value when you first got the stocks, bonds or mutual funds, said Tom Ochsenschlager, a vice president at the American Institute of Certified Public Accountants. He said he's found that some brokerages are "not very accurate" at calculating basis values. There are some Web-based calculators, but the best resource is the original paperwork.

Charitable deductions. The IRS has tightened rules for charitable deductions, and you now must have paperwork to back up any donations you claim. "Make sure you've got that documentation before you put it on the form," Ochsenschlager said.

Homebuyer tax credit. If you plan to buy a house this year, Scharin suggested seeking an extension from the IRS instead of filing. A new $8,000 first-time homebuyer's credit for purchases through Dec. 1 can be claimed on last year's taxes, Scharin noted, so it could make sense to delay filing until the closing.

Need more time?

Six-month extensions require filing IRS Form 4868, and you will have to pay estimated taxes if you think you owe the IRS.

If you don't have an extension approved, file your return, even if you need to work out a payment arrangement. The penalties for filing late are much harsher than the penalties for late payment.

Most tax experts advise filing electronically, which many people can do for free through the IRS' FreeFile program. But many post office branches stay open until midnight on April 15 to make sure you get that all-important postmark.