The length of time you should keep a document depends on the action, expense or event. Generally you should keep a copy of your tax return and your records that support an item of income, deduction or credit shown on your tax return for 3 years. Health care information statements should also be kept for 3 years.
Keep records for 6 years if you do not report income that you should report, and it is more than 25% of the gross income shown on your return.
Keep records relating to real estate for 7 years after disposing of the property.