What 2017 tax records can you toss once you’ve filed your individual return? None. But it’s the perfect time to go through old tax records and see what you can discard. A common rule of thumb is to keep tax records for at least six years from filing, after which the IRS generally no longer can audit your return or assess additional taxes, even if your income was understated. But hang on to certain records longer. Examples include tax returns themselves, W-2 forms, and records related to real estate, investments or retirement accounts.