Should I keep my old tax returns? If so, for how long?
Yes, keep your old tax returns.
One of the benefits of keeping your tax returns from year to year is that you can look at last year's return while preparing this year's. It's a handy reference and reminds you of deductions you may have forgotten.
Another reason to keep your old tax returns is that there may be information in an old return that you need later.
Audits and your old tax returns
Here's a reason to keep your old returns that may surprise you. If the IRS calls you in for an audit, the examiner will more than likely ask you to bring your tax returns for the last few years. You'd think the IRS would have them handy, but that's not the way it works. More than likely, your old returns are stored in a computer, in a storage area, or on microfilm somewhere. Usually, your IRS auditor has just a report detailing the reason the computer picked your return for the audit. So having your old returns allows you to easily comply with your auditor's request.
How long should I keep my old tax returns?
You may want to keep your old returns forever, especially if they contain information such as the tax basis of your house. Probably, though, keeping them for the previous three or four years is sufficient.
If you throw out an old return that you find you need, you can get a copy of your most recent returns (usually the last six years) from the IRS. Ask the IRS to send you Form 4506, Request for Copy or Transcript of Tax Form. When you complete the form, send it, with the required small fee, to the IRS Service Center where you filed your return.