According to the Internal Revenue Service (IRS) you should keep your supporting documentation for at least three years. More information on what you should keep and for how long can be found in IRS Publication 17.
Some things to consider:
• W-2, Wage and Tax Statement or 1099 Form (for independent contractors);
• Bank and brokerage statements for an end-of-the year accounting of earned interest or stock earnings, life insurance policies that have a cash value or investment component;
• Receipts, credit card bills or canceled checks for expenses such as mortgage interest, real estate taxes, alimony or child care; and,
• Written acknowledgements from donations to charitable organizations. This information should be stored in a safe place, such as a safety deposit box. Also, keep an inventory list of your records in another safe place.