I was told by SS that you are to report all income. At the end of each year, once taxes are done the next tax season, they will get IRS statements to the effect of your income to verify otherwise whether or not a given month(s) will have met the criteria for a trial work period month, if it goes over $770, this year's amount. If you are within guidelines and have not used us your TWP months, you will not owe but if you let it go and used up your TWP months and are still earning over 770, you could find yourself in a position that you have to pay back your social security.