Daylight saving time starts Sunday. Here are 7 things to know as clocks spring forward.

Embrace it or begrudge it, we’re all in for a significant change in our lives. On Sunday, a second after 1:59:59 a.m. it became 3 a.m. as daylight saving time begins anew in Philly. (As for whatever happened to 2 a.m., see below.)

On Sunday the sun sets as late as it did in mid-September; payback is the sun is rising as late as it did right before the winter solstice. Give yourself at least a few days: This does require a period of adjustment.

» READ MORE: 10 reasons to love standard time

In fact, even after 100-plus years of semiannual time changes, it seems that the world at large continues to undergo a period of adjustment to the very concept, with widespread disagreement on exactly when and why we should do this, or whether we should it at all.

So how did we get here, and what time did we arrive? Let’s wind back the clock.

Who started all this timekeeping business? Beats us. But based on the available evidence, from early on our ancestors recognized that the sun was subtly different at every moment. Monitoring the course of the shadows became a form of timekeeping, thus the sun dial.

What is believed to be the earliest written mention of a sundial appeared in the Old Testament roughly 3,000 years ago.

» READ MORE: Meet the man of the hour when the clocks change

Sundials eventually became popular timekeeping devices, along with water clocks — which measured time by the flow of liquid from a vessel.

Human ingenuity took a giant leap with the first mechanical clocks in the 14th century, and 700 years later, let’s just say we have some options for knowing the time.

“We do what we want, when we want,” declared Kjell Ove Hveding, leader of a movement to abolish time on the Norwegian island of Sommaroy. He then smashed a clock to the delight of supporters.

The declaration of independence three years ago was an international sensation, the story picked up by hundreds of media.

The island, 200 miles north of the Arctic Circle, sees the sun 24 hours a day for 70 days from May to July. But just how would the 300 islanders deal with work schedules, not to mention doctors’ appointments?

No worries.

“We got duped,” NPR acknowledged after it ran the story. A Norwegian embassy official contacted NPR to say the whole thing was a well-executed “stunt aimed at getting more tourists to northern Norway.” Added the official, it “certainly fooled me.”

Gulf County, Florida, is one of only a handful of counties in the country that are split into two times zones, according to the U.S. Department of Transportation.

“Visitors do get a little confused,” says Rebecca Holley, with the Gulf County Tourist Development Council.

While most of Florida is in the eastern time zone, areas west of the Apalachicola River in the western panhandle are in the central zone. That river runs right through Gulf County.

Holley recommends that visitors “manually set their cell phone to the time zone they are most familiar with.” And she advises that in the county of 15,000, “We are a very laid-back destination and we always tell people that they should never be in a hurry when visiting our shores.”

Florida remains a nexus in the time-change debate. It is one of 18 states in the last four years to have passed laws calling for year-round daylight saving time, according to the National Conference of State Legislatures.

But that can’t happen without a change in federal law. A group of senators reintroduced a bill last year to do away with the change and go all-DST all-the-time. At the time, U.S. Sen Marco Rubio (R., Fla.) declared, “The call to end the antiquated practice of clock changing is gaining momentum throughout the nation.”

Maybe we missed that story; wouldn’t be the first time. For now, on the issue of time we remain one nation, very divisible.

No clocks in Russia’s 11 time zones will be springing forward. President Vladimir Putin instituted year-round standard time in 2014.

Putin is unlikely to win any international popularity contests these days, but his clock policy is in step with the American Academy of Sleep Medicine’s thinking. The academy holds that daylight saving time is a disruption to circadian rhythms and a serious health hazard.

» READ MORE: The dark side of daylight savings time, according to sleep experts

In Ukraine, by the way, the clocks change March 27.

By congressional decree, explains Geoff Chester, with the U.S. Naval Observatory, it will never be 2 a.m. in Philadelphia on March 13, 2022. Right after 1:59:59999 ... it will jump to 3 a.m. In other words, when it’s 1:45 a.m., it also will be quarter to three.

That’s about the tilt of the Earth on its 584 million-mile trip around the sun — not the clocks.

Daylight hours have been expanding robustly the last several weeks, and the sunrise-to-sunset period on Sunday will be two-and-half hours longer than it was at the solstice on Dec. 21.

And it only gets longer from here for the next three months.