As the clocks fall back an hour this weekend, the biannual debate over the efficacy of changing clocks to prioritize evening light for half the year bursts back into life.

According to the Department of Transportation, which oversees national timekeeping, daylight saving time is observed between the second Sunday in March and the first Sunday in November for three reasons: to commute and run evening errands in the daylight, to save energy in the evening, and to prevent crime.