Don’t stay out too late Saturday — you’ll need all the sleep you can get.

Daylight saving time begins Sunday, meaning one less hour of sleep, as most of the nation moves clocks ahead one hour.

Love it or hate it, springing forward and falling back is a practice that dates back decades. Here’s what to know about it.

When does daylight saving time start and end?

For 2019, daylight saving time begins Sunday, March 10, at 2 a.m. and ends 2 a.m. Sunday, Nov. 3. But it’s not the same date every year. DST starts the second Sunday of each March and ends the first Sunday of November.

What is the origin of daylight saving time?

Some point to Benjamin Franklin, though the Franklin Institute is quick to clarify that Franklin didn’t invent DST, but rather suggested in a 1784 satirical essay that Parisians adjust their sleep schedules to cut down on lighting costs.

George Hudson, a New Zealand entomologist, presented the idea in 1895, according to the Franklin Institute, while the New York Times credited the “first idea to move the clock hands” to William Willett, who unsuccessfully pitched it to the British Parliament in 1908. Germany adopted the practice in 1915 to save money during wartime. Britain and the United States soon followed, according to the Times.

After World War I, daylight saving time became the decision of local lawmakers, according to NPR. The Uniform Time Act of 1966 established peacetime daylight saving time nationwide.

Why do we still have daylight saving time?

The nation keeps DST around to “save energy,” according to the Department of Transportation, which oversees daylight saving time as well as time zones.

“People tend to spend more time outside in the evenings during daylight saving time, which reduces the need to use electricity in the home,” the department says. “Also, because the sunrise is very early in the morning during the summer months, most people will awake after the sun has already risen, which means they turn on fewer lights in their homes.”

Daylight saving time also prevents traffic injuries and reduces crime, according to the department. But some data suggest otherwise.

Does everyone use daylight saving time?

No. Hawaii, American Samoa, Guam, Puerto Rico, the U.S. Virgin Islands, and most of Arizona don’t participate in the change. State Rep. Russ Diamond, a Republican from Lebanon County, wants the Keystone State to join that list.

“Changing clocks twice every year simply because ‘we’ve always done it that way’ is not enough reason to continue the practice,” Diamond wrote in a recent op-ed for the Inquirer.

Does daylight saving time affect health?

It’s no secret that skipping out on the recommended seven to nine hours of sleep a night can have negative health effects, including a greater risk for heart disease, diabetes, asthma, and depression.

There’s also a small jump in fatal accidents the Monday after daylight saving time starts, while the switch back to standard time in the fall is connected to a short-term increase in assaults, the Inquirer reported last year.

What else do I need to know?

Fire departments routinely use the clock changes to remind people to test their smoke alarms. The Philadelphia Fire Department encourages anyone in need of smoke alarms to reach out to Philly311 on Twitter or dial 311.