A. If you use e-file, it's advised to keep your tax returns indefinitely.
IRS generally has three years after the due date of your return to initiate an audit (it could extend to six years if you under-report more than 20% of your income). But there are many reasons to keep past tax returns for as long as possible, for example:
- to establish the cost basis of investments
- to contest an error on your social security benefits
- to show depreciation has been taken for property