(NEXSTAR) — Whether you’re an avid football fan or just tuning in to spot your favorite celebrity, you may find yourself puzzled by the twice-a-game two-minute warning. 

If you’re unfamiliar, the two-minute warning is an automatic timeout that occurs during NFL games. It happens when the game clock hits the two-minute mark at the end of the second and fourth quarters. 

After the two-minute warning, certain clock running rules also take effect.

But why does the NFL stop the game and change some rules with just a few minutes left in the half?

As you may have guessed, the two-minute warning does offer another opportunity for commercials, which of course have monetary value. It also has value to teams, who view it as a bonus timeout, former NFL quarterback Rich Gannon told the Los Angeles Times in 2016.

Despite its modern benefits — more ad time and an extra break — the two-minute rule once served a more necessary purpose.

Pro Football Hall of Fame archivist Jon Kendle explained to the LA Times that when pro football games started in the late 1890s, there was no clock for teams and coaches to check on the scoreboard. Instead, officials were advised to notify team captains when time was running out in the half — usually when there were five to ten minutes left (the game had two 45-minute halves at the time). 

As years went by, the game got shorter. By 1942, the rules changed and the warning was given at the two-minute mark, Kendle said. Seven years later, the rules changed again, calling for a timeout when the two-minute warning is given. 

The two-minute warning became less of a warning in the 1960s after the NFL decided to use the stadium clock as the official game clock (that’s why you’ll sometimes see the official ask for time to be added).

As we mentioned before, there are different rules for certain plays after the two-minute warning. 

For example, if there is an injury timeout after the two-minute warning, the team of the injured player will be charged a timeout, if they haven’t already used the three they get per half, according to the NFL rulebook. Teams are also not allowed to commit fouls — like intentional grounding or throwing an illegal pass — in order to conserve time. 

So while your team strategizes on how to use the last two minutes of the half or game, you can take those two minutes to refill your snack plate or check in on your fantasy team.