A reader asked us, "What do I do if I discover that I goofed and submitted a tax return with an error in it? Turn myself in to the IRS?"

The answer? Not exactly. The tax form you prepare and mail in isn't the only one you're ever allowed to file for that year. After you've filed the regular return, if you need to, you can file an amended return via form "1040X." In fact, you can even amend an amended return. You're permitted to amend your return until three years have passed since the date the original return was filed (or its due date). Also, if any of your changes affect your adjusted gross income, you'll probably want to amend your state return, too. Contact your state tax department for the appropriate forms.

For example, imagine that it's the year 2039 and the rules regarding amended return deadlines haven't changed. You file your return for the tax year 2038 on April 4, 2039 -- 11 days before the filing deadline of April 15, 2039. You'll have three years in which to amend your return. The last day on which you can file an amendment will be April 15, 2042, three years after the initial due date.

Learn more in our Tax Center and our Tax Strategies discussion board. Also useful is the IRS website.

And by the way, if thinking about investing makes your head hurt and you'd like an actual person (a financial pro, no less) to talk to about your financial situation, look into our TMF Money Advisor. It's a valuable service we're offering, featuring customized independent advice from a variety of objective financial experts.