Letting teens sleep in could save the US over $9 billion dollars a year. Studies show teenage brains are wired to stay up and wake up late, they need 8 to 10 hours of sleep per night, and that school therefore starts too early. It is estimated that high school classes starting after 8:30 am or later would improve student health, boost graduation rates, raise lifetime earning potential, and lower the risk of fatigue-related car crashes, all of which could potentially contribute at least $83 billion to the US economy within a decade. Source Source 2 Source 3