According to the IRS, you should keep a copy of your 2012 tax return and all documents used to create it, in case the return is audited.
“Generally, all individual federal tax records should be kept for three years,” said Bill Brunson, IRS spokesperson. “Other documents, such as records relating to real estate dealings, stock transactions, retirement accounts and business or rental property, should be kept longer.” The same rules apply to either paper or electronic records.
Tax records can include bills, canceled checks, credit card receipts, invoices, mileage logs and any other records that support deductions or credits claimed on your return.
For more information on what kinds of records to keep, see IRS Publication 552, Recordkeeping for Individuals, which is available at IRS.gov or by calling, toll free, 1-800-TAX-FORM.