Two things can cause Social Security to decide that you are no longer disabled and to stop your benefits.
Your disability benefit will stop if you work at a level they consider “substantial”. In 2017, average gross earnings (per month) of $1170 for a non-blind individual and $1950 for blind individuals are considered substantial.
Your disability benefits also will stop if they decide your medical condition has improved to the point that you are no longer disabled. Ongoing Continuing Disability reviews are mandated by the law. If your doctor indicates that there has been no change or improvement in your condition, that is usually enough to stop the review. Be certain to promptly appeal all negative decisions.
You are responsible for promptly reporting any improvement in your condition or return to work. Be sure to send certified letters when reporting income.