When we think of daylight saving time, most of us just know the basics—spring ahead and fall behind—we’re either gaining or losing an hour of sleep. However, the history and details behind this biannual occurrence is much more complex than that.

Before you set the clocks back this year, brush up on a few interesting facts about daylight saving time.

• Contrary to popular belief, Benjamin Franklin did not originate the idea of moving clocks forward. He only proposed a change in sleep schedules—not the actual time itself.
• We can thank Englishman William Willett for leading the first campaign to implement daylight saving time in 1905.
• The general concept behind the changes is simple. In the spring, we move an hour of sunlight from the early morning to the evening, when we are more likely to do more with the light. In the fall, we lose an hour merely to return to standard time.
• At first, the American agriculture industry was deeply opposed to the time switch when it was first implemented on March 31, 1918. In their minds, the sun, not the clock, dictated their schedules.
• Hawaii and Arizona—with the exception of the state’s Navajo Nation—do not observe daylight saving time.
• The time change starts at 2 A.M. with hopes that most people will sleep through it.
• Numerous studies show that the extra hour of sleep that we lose by springing ahead can affect our health in various ways. An increased risk of heart attack, stroke, and weakened immune system have all been linked to the change.
• Until recently, losing an hour of daylight in the fall proved to be a problem for the candy industry. In fact, they lobbied for an extension to push it back after Halloween night. In 2007, a law extending daylight saving time into November went into effect, and now children have an extra hour of daylight to trick-or-treat, and consume more candy!