According to the Income Tax Act of 1961, there's no specific requirement for how long individuals should keep their old ITR documents.
However, under Section 149 of the Income Tax Act, the IT department has the authority to issue notices for up to a 10-year period in cases of income escaping assessment.
For instance, If someone filed their ITR in FY 2023-24, they should retain these documents until FY 2033-34.
Therefore, it's prudent advice for ITR filers to retain their ITR papers for a minimum of 10 years to ensure compliance with potential future assessments.