When you fail to file taxes in time, IRS will determine penalties of late filing and it can impose interest on any unpaid tax as of the due date. The more time you take in doing it the greater the punishment. The IRS is allowed to submit a Substitute for Return which usually bloats your tax bill since it does not include any deductions and credits. In the long run, you will have tax liens, levies or garnishment of wages. In case of refunds it can be lost after some period of time. Easy filing reduces penalties, secures your refund and preserves your tax filing. What Happens If I Don't File Taxes