SALEM, Ore. (CNN/Money) – Tax season is officially here.

The deadline for mailing W-2s and other tax forms is January 31, which means you should have all of your tax documents in hand in time for the weekend. Depending on how disorganized you've been, you may need the good part of a weekend to prepare your return.

The Internal Revenue Service estimates that, on average, it will take taxpayers a total of 13 hours and 35 minutes to gather paperwork, brush up on tax code and complete the Form 1040. A Schedule A will add another five hours and 37 minutes to the task, and a Schedule C will add an estimated 10 hours and 55 minutes.

These estimates are based on a computer model, said IRS spokesman Anthony Burke, not a survey of actual filers.

If you ditch the pen and paper and use one of the many tax software programs available, you may save time and avoid errors. Check out the software available for free from the "Free File" alliance created by the IRS to encourage e-filing.

You might also have the option of filing Form 1040EZ or Form 1040A this year. "There is a larger income limit for the simple tax form," said CCH Incorporated principal analyst Mark Luscombe.

"You still have to have a simple tax life and not take itemized deductions, but whereas before you need taxable income of less than $50,000 you can use the form if you income is less than $100,000."

If time is money, you could just hire a pro to do the job for you. Last filing season, the average cost of a professionally prepared return was $140, according to H&R Block. You'll get more for your money if you get your information in early, before the tax crunch.

The good news – for most taxpayers – is that there is probably a refund check for all your trouble.

The average refund for 2003 returns was $2,063, according to IRS stats through April 30, 2004. Refunds this tax season may not be quite as large as they were for 2003 when there were mid-year tax cuts, said Luscombe.

OK, so you probably won't do your taxes as soon as you get your W-2.

You'll feel better about procrastinating if you start organizing your records and make a checklist of the forms and receipts you'll need. Use your 2003 return as a guide.

Kathy Burlison of H&R Block also suggests using your 2004 calendar. "Look at your calendar from last year to jog your memory about a business trip you forgot about or a donation you made," she said.

In the case of most donations, you need to write the check or hand over your credit card before the end of the year to get the tax deduction. This year, there is a notable exception. If you donate to certain charities help victims of the tsunami in Asia in January, you have the option of deducting that gift on your 2004 taxes.

Although there weren't a lot of changes to the tax code in 2004, one notable change was that in 2004 and 2005 taxpayers who itemize their deductions have the option of claiming their state and local sales tax instead of state and local income taxes.

"States with no income tax complained that their taxpayers were at a disadvantage, so now everyone has the choice of deducting sales or income tax," said Martin Nissenbaum, national director of personal income tax planning for Ernst & Young.

If you didn't save all your receipts don't worry. "The law was passed in October, so if you're not the kind of person who saves every receipt you can use a table based on your income and family size," said Nissenbaum, adding that these tables don't account for city and county taxes, which are also deductible. Click here to download the IRS table.

"In states where there is no income tax it's a no brainer," said Nissenbaum.

If you live in a state with no sales tax, such as Oregon, it's probably also a no brainer unless you shop outside your state and have the receipts to prove it.

Otherwise, you'll want to look at your income and spending to see which deduction makes sense. "In Florida, there is no income tax but there is an intangible tax, so they will be able to deduct both," said Nissenbaum.

Stay tuned for more articles to help you survive tax season, including overlooked deductions, audit red flags and everything you ever needed to know about your home office and taxes.