Tax records should always be kept for at least 7 years but some Tax records may only need to be kept for 3 to 4 years.
But just to be safe and have them on hand should you need them you should always keep any Tax records for 7 years which is what I do.
I file away all my Tax records for 7 years minimum and then if I no longer need those tax records after 7 years I can then destroy them.
It's always better to have your tax records needed and available just in case because you never know but after 7 years you should no longer need those tax records.