Marvin Lewis’s time as head coach of the Cincinnati Bengals is expected to come to an end after this season. It has been a remarkable run of longevity given that Lewis has compiled a 0-7 playoff record in 15 seasons on the job. No head coach in NFL history has more playoff losses without a win than Lewis.

Lewis, who was hired by Cincinnati in 2003, is one of seven active coaches to have started his current job prior to the 2010 season. It’s an illustrious group that includes Bill Belichick, Mike McCarthy, Sean Payton, Mike Tomlin, John Harbaugh and Pete Carroll. Next to those names, Lewis sticks out for an obvious reason: Every coach on the list has won a Super Bowl on his current team. But perhaps more telling, each one of them did so within five seasons on the job.

This is strikingly common in NFL history. Of the 31 head coaches to win at least one Super Bowl, 27 of them won their first championship within the first five seasons with that team. Only Chuck Noll (six years in Pittsburgh), John Madden (eight years in Oakland), Tom Landry (12 years in Dallas) and Bill Cowher (14 years in Pittsburgh) needed more than five years to capture that elusive first ring.

It could be argued that Lewis has lacked something most of those coaches enjoyed: a future Hall of Fame quarterback. Lewis never had an Aaron Rodgers or a Tom Brady. Instead, he’s had Carson Palmer and Andy Dalton, the current Bengals’ quarterback. Oddly enough, the closest Lewis ever came to winning a playoff game was in 2015, when Dalton was sidelined with an injury. AJ McCarron helped the Bengals to a late lead over the Steelers in the wild-card round, but Pittsburgh still won 18-16. That was the fifth season for the duo of Lewis and Dalton, and the Bengals haven’t made the playoffs in the two years since. Based on NFL history, there’s reason to believe that Lewis should have parted ways with the Bengals — or vice versa — after that season and not waited until now.

Call it The Five-Year Rule: No team has ever started the same quarterback under the same head coach for more than five years and seen that duo win its first championship. As you can see in the table, some really great duos just got their title together in the fifth year, but all 35 duos required no more than five years together.

Champion QB-coach duos tend to be recently formed Every coach/starting quarterback combination to win the Super Bowl by how many years together it took to get that first title, since the 1970 AFL-NFL merger Team Starting QB Head Coach 1st SB Win Years DEN Peyton Manning Gary Kubiak 2015 1 TB Brad Johnson Jon Gruden 2002 1 NE Tom Brady Bill Belichick 2001 1 BAL Trent Dilfer Brian Billick 2000 1 STL Kurt Warner Dick Vermeil 1999 1 NYG Jeff Hostetler Bill Parcells 1990 1 SF Joe Montana George Seifert 1989 1 WAS Doug Williams Joe Gibbs 1987 1 SF Joe Montana Bill Walsh 1981 1 OAK Jim Plunkett Tom Flores 1980 1 DAL Roger Staubach Tom Landry 1971 1 BAL Johnny Unitas Don McCafferty 1970 1 SEA Russell Wilson Pete Carroll 2013 2 PIT Ben Roethlisberger Mike Tomlin 2008 2 PIT Ben Roethlisberger Bill Cowher 2005 2 DAL Troy Aikman Barry Switzer 1995 2 WAS Joe Theismann Joe Gibbs 1982 2 GB Aaron Rodgers Mike McCarthy 2010 3 DEN John Elway Mike Shanahan 1997 3 MIA Bob Griese Don Shula 1972 3 NO Drew Brees Sean Payton 2009 4 NYG Eli Manning Tom Coughlin 2007 4 SF Steve Young George Seifert 1994 4 DAL Troy Aikman Jimmy Johnson 1992 4 WAS Mark Rypien Joe Gibbs 1991 4 NYG Phil Simms Bill Parcells 1986 4 CHI Jim McMahon Mike Ditka 1985 4 OAK Ken Stabler John Madden 1976 4 BAL Joe Flacco John Harbaugh 2012 5 IND Peyton Manning Tony Dungy 2006 5 GB Brett Favre Mike Holmgren 1996 5 PIT Terry Bradshaw Chuck Noll 1974 5 Only counts years that a quarterback spent as a starter. Year given is the year that season started. Source: Football Outsiders Almanac

This list raises a red flag for any quarterback-coach combination that has logged a lot of mileage together and not won it all — like Lewis and Dalton. If championship success doesn’t come within five years, things tend to get stale, and someone eventually has to move on from their position of power.

Plenty of great coach-QB combos have played together for longer periods of time without a Super Bowl, but even those pairs’ best years have tended to come early in their tenures. The great Don Shula coached Dan Marino for 13 years in Miami, but the duo reached only one Super Bowl — in 1984, Marino’s second season. Incredibly, some of the best duos to never win a championship had their best shot at one in their fifth season.

John Elway and Dan Reeves (1987 Broncos): The pair reached three Super Bowls together, but the only one that looked optimistic was Super Bowl XXII in year five, when Denver opened up a 10-0 lead before an avalanche of points by Washington buried the Broncos. Elway would win his first title with Mike Shanahan in their third year together.

Boomer Esiason and Sam Wyche (1988 Bengals): The high-powered offense was shut down by San Francisco in Super Bowl XXIII, but one more defensive stop against Joe Montana would have clinched a title.

Jim Kelly and Marv Levy (1990 Bills): The Bills lost Super Bowl XXV after Scott Norwood missed a potential game-winning field goal. Buffalo lost the next three Super Bowls as well but never came closer to winning than the first shot.

Matt Ryan and Mike Smith (2012 Falcons): The Falcons never had back-to-back winning seasons before Ryan was drafted and Smith was hired in 2008. Then they had five winning seasons in a row, but the peak was the 2012 season, when the Falcons blew a 17-point lead at home to the 49ers in the NFC Championship Game.

And more recently, Carolina’s Ron Rivera and Cam Newton reached the Super Bowl in 2015, their fifth season together, but lost to Denver. Now in their seventh year, the two are 10-4 and have an opportunity to defy The Five Year-Rule by winning their first championship this season.

A couple of other duos have also recently seen their five-year clock expire. In Arizona, this season was Bruce Arians and Carson Palmer’s fifth together. But a championship was not to be as Palmer broke his arm in Week 7, derailing the Cardinals’ season. This season was supposed to be the sixth year for Chuck Pagano and Andrew Luck in Indianapolis, but Luck couldn’t even get on the field in his recovery from shoulder surgery. Pagano is unlikely to return in 2018, while fans just hope that Luck can return to action.

Finally, there is the intriguing case of Andy Reid and Alex Smith in Kansas City, who are in the middle of their fifth season together. Reid and Smith already have some history working against them: Reid is in his 19th season as a head coach, and Smith is in his 13th season. Only one quarterback (Elway, 15th season) and one head coach (Cowher, 14th season) won their first championship more than a dozen years into their careers.

After a roller-coaster season, Kansas City has rebounded in recent weeks, easily dispatching of the Raiders and Chargers to regain control of the AFC West. Smith is enjoying a career-best season, but this fifth try may very well be his last shot at leading the Chiefs to a championship.

If Smith and Reid can’t bring home the trophy, their tenure together may be over. The Chiefs are likely to obey The Five-Year Rule and give another combo a try — as the Bengals and Lewis probably should have done two years ago.

Check out our latest NFL predictions.

CORRECTION (Dec. 21, 5 p.m.): A previous version of this article contained two errors. First, it referred incorrectly to Alex Smith as a free agent. He will hit free agency after the 2018 season. Second, the table in this article incorrectly said that Aaron Rodgers and Mike McCarthy won a Super Bowl after five seasons together. The Packers won the 2010 Super Bowl in Rodgers’ third year as a starter.