if someone hasn't filed taxes for a while how many years back do they have togo?

Answer 1

Any tax year that you haven't filed a return for is considered open. An open tax year is fair game for the IRS regardless of how long ago it was. They can go back 50 years if they wanted to though that would be unusual. Not impossible, just unusual.

For most taxpayers, not filing won't actually hurt you as far as the law is concerned since most folks are due a refund anyway. The only penalty for late filing is based on the tax that was due with the return -- no tax due = no penalty due. BUT you only have 3 years from the due date of the return to claim that refund so it's in your best interest to file by the due date.

Also, some exclusions, credits, and deductions require a timely return to be filed. That can take you from being entitled to a refund to owing a huge tax bill in some cases. A classic example of that is the Foreign Earned Income Exclusion; that one has burned many American ex-pats living overseas who erroneously thought that they didn't need to file a return since they lived outside of the US.

Answer 2

You go back to the last year you filed, not so much to see if they owe you anything, but just to be sure you dont own them anything, even if your positive you dont owe, its better if you go to them rather then them come looking for you, play it safe.