American football
Football games last for a total of 60 minutes in professional and college play and are divided into two-halves of 30 minutes and four-quarters of 15 minutes. High school football games are 48 minutes in length with two-halves of 24 minutes and four-quarters of 12 minutes. The two-halves are separated by a halftime period, and the first and third quarters are also followed by a short break. Prior to the start of the game, the referee and team captains for each team meet at midfield for a coin toss. The visiting team is allowed to call 'heads' or 'tails'; the winner of the toss is allowed to decide between choosing whether to receive or kick off the ball or choosing which goal they want to defend, but they can also defer their choice until the second half. The losing team, unless the winning team decides to defer, is allowed to choose the option the winning team did not select, and receives the option to receive, kick, or select a goal to defend to begin the second half. Most teams choose to receive or defer, because choosing to kick the ball to start the game would allow the other team to choose which goal to defend. Teams switch goals following the first and third quarters. If a down is in progress when a quarter ends, play continues until the down is completed.
Official (American football)
Because their regular season spans only 17 weeks, the NFL is one of only two major sports leagues in the United States that only pay their officials on a contract basis as opposed to being full-time salaried employees, the other being Major League Soccer. Advantages to this system include being able to eliminate unqualified officials simply by not offering them a contract the following season, where terminating full-time employees would require them to show cause. Critics argue that full-time officials would be free from the distractions of a second job, but proponents of part-time officials point out that the NFL would lose a number of qualified officials because many of them are owners, presidents, or CEOs of various companies. Proponents also argue that there is only one game per week and the regular season is only four months long, and that having full-time officials does not necessarily guarantee that they will make fewer officiating mistakes. The level of training and review in which NFL officials participate makes additional time redundant. In any event, veteran officials can earn substantial salaries for their work. The NFL Referees Association serves as the union that represents officials in the NFL.