how long should accounting records be kept
If a substantial amount of income is omitted from the return, the period is extended to six years. Many advisers suggest that you can dispose of tax records after seven years. But some tax records need to be kept longer. Copies of prior tax returns and elections they contain should probably be preserved indefinitely. Records supporting the cost basis in assets owned, such as buildings and long-lived equipment, should be retained until at least three years after the asset is disposed of.