One of the biggest nightmares to straighten out is someone stealing your name and social security number and filing a fake tax return with that information.  It can take up to a year to straighten out the mess and your refund is held until it is done.  But, a very simple added precaution can stop those thieves dead in their tracks.  It is called an IP Pin.  If that pin number is not on your return, (you get a new one each January) then the IRS will not accept your return electronically.  Period.  So they can steal my name/SS# and try to file a return to get that free government money, but it will do them no good.