Tax records should be kept for a period of 3 years from the date you filed your original tax return or 2 years from the date you paid the income tax.
However if you file a claim for a loss from worthless securities or bad debt deduction then you should keep those tax records for a minimum of 7 years.
I personally just keep all my tax records for 7 years just in case I need them then after 7 years I get rid of the unneeded tax records.