California’s Democratic governor finished the Legislative session on Sunday by rejecting expansions of full-day kindergarten programs and paid family leave for teachers. He did, however, sign one new bill into law that many say is just good common sense — and won’t really cost anyone anything.

Newsom signed a bill that would require high schools to not begin classes until 8:30 am. Middle schools will be required to start no earlier than 8 am.

This is something science says is a good idea:

The call for letting teens sleep comes from the American Academy of Sleep Medicine (AASM), with a position statement published in the Journal of Clinical Sleep Medicine. For middle and high school students, it says, the school day should begin at 8:30 am or later. The group recommends 13 to 18 year-olds should regularly sleep 8 to 10 hours, yet data from the Centers for Disease Control show almost 70 percent of high school students report sleeping 7 hours or fewer on school nights.

The problem is that many schools just aren’t designed for teens’ circadian clocks, which shift about two or three hours later as they hit puberty, before shifting back in their early twenties. Changing biology makes it harder for them to fall asleep early, and combined with waking up early that can result in chronic sleep loss.

“Starting school at 8:30 AM or later gives teens a better opportunity to get the sufficient sleep they need to learn and function at their highest level,” said lead author and AASM Past President Nathaniel Watson in a statement. Later start times have also been recommended by the Centers for Disease Control and Prevention, the American Academy of Pediatrics, and the American Medical Association. Interestingly, that Canadian study went even further, recommending a 9:30 am start.

Gov. Gavin Newsom had until Sunday to act on legislation passed this year. On Sunday night, Newsom announced he had signed 870 laws. But Sunday’s action included more vetoes than signings, mostly for things Newsom said the state could not afford to implement.

Among those bills were one to expand paid family leave for teachers. Newsom said he was committed to obtaining this for all Californians but this bill would only blow up the budget without achieving those ends.

Another rejected bill was to expand full-day kindergarten for all California children. It would require all school systems with an elementary school to provide it — including charter schools. Newsom said the price tag was just too high but did add that there was a 300 million dollar stipulation included in the budget to further expand full-day kindergarten.