When keeping Tax Records it's best to keep your Tax Records for up to 7 years.
Some Tax Records can be kept for only 3 years while others can be kept for up to 2 years but it's best to keep all Tax Records for up to 7 years.
You never know when you might get audited or need the Tax Records so if you haven't needed the Tax Records in 7 years then you can dispose of them and get rid of them.
Make sure to shred up any important paperwork that has personal information on them to avoid Identity theft.
According to the IRS from the IRS website they mention the following.
Keep Tax records for 3 years from the date you filed your original return or 2 years from the date you paid the tax, whichever is later, if you file a claim for credit or refund after you file your return.
Keep Tax records for 7 years if you file a claim for a loss from worthless securities or bad debt deduction.
I keep all my Tax Records for 7 years just in case I need them as it's better to have them when and if you need them.