The IRS says “it depends.” Different situations have different limitations periods (e.g., how long the IRS can go back to second-guess what you did). The following is a list of general guidelines based on current (7-21-2022) advice:

1. Keep records for 3 years if situations (4), (5), and (6) below do not apply to you.
2. Keep 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.
3. Keep records for 7 years if you file a claim for a loss from worthless securities or bad debt deduction.
4. Keep records for 6 years if you do not report income that you should report, and it is more than 25% of the gross income shown on your return.
5. Keep records indefinitely if you do not file a return.
6. Keep records indefinitely if you file a fraudulent return.
7. Keep employment tax records for at least 4 years after the date that the tax becomes due or is paid, whichever is later.

Source: IRS.gov: How Long Should I keep Records?