Don't forget your Social Security number
By Kay Bell • Bankrate.com

Each of us has occasionally felt like Homer Simpson. Confronted by some silly mistake we made, we slap our forehead and mutter "D'oh!"

But when it comes to taxes, that "D'oh!" can cost dough. Sometimes the error means we have to pay more in taxes. Other times it delays the refund we're expecting from the Internal Revenue Service.

One of the most common mistakes is omitting Social Security numbers on your 1040 form. If you forget to include these IDs -- for yourself, a spouse or any dependents -- you could face tax trouble. The IRS won't process your return with your number, and some tax breaks could be disallowed. Here's how to avoid this mistake and get through tax-filing season with a fuller bank account and your good humor still intact!

Not including Social Security numbers
A couple of years ago, the IRS stopped putting taxpayer Social Security numbers on the tax package labels. Privacy advocates were concerned that this information could be too easily used by others.

Unfortunately, the IRS found that removing it also meant that taxpayers forgot to write in their identification numbers on their tax returns.

It's now up to you to fill in your Social Security number, as well as your spouse's if you file jointly and those of any dependents you claim. This is crucial because there are so many transactions -- income statements, savings account interest, retirement plan contributions -- keyed to this number. The identification numbers also are vital when the IRS checks any tax credits you apply for, like the Child Tax and Additional Child Tax credits, as well as credits for educational expenses and dependent care.

If your kids don't have their Social Security numbers yet, contact the Social Security Administration immediately and, if necessary, send the IRS Form 4868, Automatic Extension of Time to File, to make sure you have plenty of time to get the number and fully complete your return.

Getting the identification number or numbers on your forms -- legibly and correctly -- means the IRS will get it right when they check your return. Just one wrong or transposed number in your Social Security number could delay your refund or result in a disallowed credit or allowance.

-- Updated Dec. 17, 2004