The NFL is often referred to as the Not For Long league. Careers can end in an instant, and not just because of the brutal physicality on the field.
Things can be equally rough off the field and even the greats can be shoved aside if they stop contributing to their team's success.
With Bill Belichick's New England Patriots languishing at the bottom of the AFC East, rumours have begun to spread that he could soon be fired.
Belichick is without doubt one of the league's greatest coaches. Many would argue that his six Super Bowl titles as a head coach - more than anyone else in the history of the league - would qualify to rank him as the greatest.
Regardless, Belichick's last title came in 2019 and he has struggled to produce an effective team since the departure of fellow future Hall of Famer Tom Brady.
We take a look at some of Belichick's peers and how those coaching greats' careers ended.
Bill Parcells
Bill Belichick's ascent to greatness began as the defensive coordinator of Bill Parcells' New York Giants.
Big Bill (Parcells) and Little Bill (Belichick) won two Super Bowls together in New York. Parcells then headed to New England where he lost Super Bowl XXXI to the Green Bay Packers.
He took the New York Jets to the AFC Championship Game in 1998 before moving to Dallas where he achieved two wild card play-off losses in four seasons. Having already 'retired' twice before, Parcells took his third and final retirement after the wild card loss to Carolina in 2006.
Tony Dungy
Tony Dungy was twice the NFL Coach of the Year and led the Tampa Bay Buccaneers and Indianapolis Colts to Super Bowl victories in 2002 and 2006 respectively.
In 13 seasons, he missed the playoffs just twice (in his first and third seasons as head coach) and won five consecutive AFC South titles with the Colts. After a wild card playoff defeat in 2008, Dungy retired and moved into broadcasting.
Don Shula
The all-time leader in NFL wins as a head coach and the architect of the only undefeated season in NFL history with the Miami Dolphins, Shula is undoubtedly on Belichick's level.
He won two Super Bowls in his career, coaching 25 seasons with Miami. Shula retired after a wild card playoff defaet to the Buffalo Bills in 1995.
George Halas
'Papa Bear', one of the co-founders of the NFL, and second on the all-time list of NFL wins is an icon.
Coaching from 1920 to 1967, with some gaps in between here and there, he won eight NFL championships (the precursor to the Super Bowl).
His last championship came in 1963 and four mixed seasons followed. His final year was the 1967 season in which the Bears were pipped to the NFL Central title by the Green Bay Packers after going 7-6-1.
He retired in May of 1968 as the first coach to reach 300 wins in the NFL.
Tom Landry
The face of the Dallas Cowboys' first great era, and immortalised in The Simpsons because of his hat, Tom Landry won two Super Bowls in 28 years as Dallas head coach.
Following a defeat in the 1985 Divisional round to the LA Rams, Landry's Cowboys slipped under 0.500 for the first time in decades in 1986. Landry's last year was a rough 3-13 that saw them finish bottom of the NFC East.
Jerry Jones bought the team and made firing Landry his first significant act as owner.
The decision was met with huge opposition but Landry did not coach again.
Curly Lambeau
The man for whom Green Bay's Lambeau Field is named, coached 33 years in the NFL across Green Bay, Chicago, and Washington. His four seasons outside Wisconsin, two each in Chicago and Washington, were rather unimpressive.
He won six championships in Green Bay, losing another NFL Championship to New York in 1938, but went a collective 17-28 after leaving. His last season was 6-5-1 in Washington, after which he retired.
Chuck Noll
Noll won four Super Bowl titles in six seasons in Pittsburgh, reaching the playoffs 12 times in a 22-year stretch in the Steel City.
His final season saw Pittsburgh struggling at 5-9 before two late wins improved their record to 7-9, allowing Noll to retire with his dignity intact.