Marino stuck around longer than many elite quarterbacks. Joe Namath, Terry Bradshaw, Troy Aikman, Jim Kelly, Boomer Esiason and Dan Fouts all retired between the ages of 34 and 36.

Other quarterbacks were just getting started.

Many ridiculed the Raiders for signing journeyman Rich Gannon in 1999. Gannon was 34. He had started only 58 games. Yet those fresh legs came in handy. With the Raiders, Gannon made four Pro Bowls. He won a regular-season MVP and an AFC Championship.

"Early in my career, it's like I was sleepwalking," said Gannon, now a CBS analyst. "You don't know what you don't know. As a young player, I had no idea. I wasn't nearly as prepared as I should have been or could have been. I wasn't trained that way. I didn't really know how to prepare for a game."

He had streamlined his training enough that he believes he could have been productive into his 40s if not for a neck injury suffered in 2004. Phil Simms also played to age 39. In his final season for the Giants, he finished 11-5, and posted the highest completion percentage of his career.

"There is no question I could have played a few more," said Simms, also a CBS analyst.

But the Giants chose to go with the unproven Dave Brown and Kent Graham, so Simms retired.

That's one reason that many quarterbacks retire before 40: their team wants to get younger and cheaper. When the Packers stood firm on promoting Aaron Rodgers to the starting spot, Favre chose to keep playing elsewhere. Just as when the 49ers elected to elevate Steve Young, Joe Montana accepted a trade to Kansas City, and led the Chiefs to two playoff appearances.

Many have no choice but to retire in their 30s. Troy Aikman and Steve Young retired due to concussions. Joe Theismann retired due to a severely broken leg.

Others just keep going.

Warren Moon is in the Pro Football Hall of Fame largely on the strength of his play long after many contemporaries had retired. He played in the CFL until age 28. He established himself as one of the NFL's most prolific passers during 10 seasons with the Houston Oilers. Still, they wanted to turn the offense over to Cody Carlson, so they dealt Moon to Minnesota.

"I played seven more years," said Moon, who threw 8,492 yards his first two seasons as a Viking. "Cody only played one. But if I was a general manager, I would have made the same decision. They want to see the guy they put all their money and time into. Economically, it's often better to play a younger player."

Moon had the body of a younger man. He never suffered a serious injury, and he had maintained a strict diet, massage and chiropractor regimen.

"Some don't take care of themselves until they feel their body change or their skills deteriorate," said Moon, a Seattle Seahawks radio analyst. "It's almost too late at that point."

Late in a career than included years in Houston's quick-trigger run-and-shoot, Moon could think at warp speed. He felt like he was always a step ahead of the defense, knowing where he was throwing by the third or fourth step of his drop, allowing him to get a pass to its target quicker than the kid who threw with more velocity.

Moon also attributed his success to the chip always on his shoulder — every time he played poorly or tweaked an ankle, observers attributed it to age.

Many say the the same in regard to Favre if he stumbles. As he noted Wednesday, he has a daughter who is only a few years younger than some of his teammates. And after remarking that Favre's "peers" had voted him a captain, Jets coach Eric Mangini smiled and corrected himself: "The kids voted him in."

What's changed over the years?

"As I've gotten older, I would like to sleep in a little longer," Favre said of game day.

Favre used to be an early riser, pacing as he pined for kickoff, and his roommate Frank Winters would tell him to settle down and go back to sleep.

"I kind of feel like Frank now," Favre quipped.

When does he get excited?

"When the first guy chases me," Favre said.

Chasing him like Father Time.

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