Which brings us to Peyton Manning.
Manning's skills certainly showed no evidence of erosion this season. The soon-to-be-38-year-old Broncos quarterback set NFL records for touchdown passes (55) and passing yards (5,477) and is expected to earn his fifth league MVP award this week, and, oh yeah, has his team in the Super Bowl for the third time.
Then again, if the Broncos beat the Seahawks in the Meadowlands on Sunday, wouldn't that be the perfect way for Mr. Buick to end his career? On top, with a second Super Bowl ring and a one-for-the-thumb MVP award?
There's only one problem. Manning isn't ready to retire. He'd love to go out on top. But not now. Not yet.
"I know there are a number of players that have walked away as champions," Manning said yesterday after the Broncos arrived in North Jersey for Siberian Super Bowl I. "And I'm sure that's a great feeling for those people. John Elway did it. Ray Lewis. Michael Strahan.
"But in talking to Ray and John, they couldn't play anymore [when they retired]. That was all they had to give. They surely left it all out there."
It was pretty obvious that Lewis' tank was completely empty when the Ravens won the Super Bowl last year. He contributed a lot more leadership than big plays to the effort. He knew it was time to say bye-bye.
Same with Elway, who leaned heavily on running back Terrell Davis (2,008 yards, 21 rushing TDs) when the Broncos won the second of their back-to-back Lombardi Trophies after the 1998 season.
Elway, now the team's executive vice president, is the guy who took a chance on Manning 2 years ago when he was coming off of not one, not two, not three, but four career-threatening surgeries on his neck.
"I still think he's young and playing well," Elway said of Manning. "But that [retirement decision] is going to come down to Peyton. It's going to come down to what he wants to do.
"Having been a football player, when you leave this game, you want to leave it on your last leg and try not to leave anything on the table. Anybody that's a competitor, that's kind of the way you want to leave the game."
Given the way Manning is playing this season, it sure does appear that there still is a 30-pound turkey and all the trimmings on the table. Win or lose Sunday, the only way this will be his last season is if his doctors discover that he has done further damage to his neck.
"I certainly had a career change 2 years ago with the injury and changing teams," Manning said. "I truly have taken it on a 1-year-at-a-time basis. I really had no plans beyond this game. I had no plans coming into this season beyond this year. I think that's a healthy way to approach your career at this stage.
"But I still enjoy playing football. I feel better than I thought I would at this point, coming off that surgery. I still enjoy the preparation part of it, the work part of it. Everybody enjoys the games. Everybody's going to be excited to play in the Super Bowl.
"But when you still enjoy the preparation and work part of it, I think you still ought to be doing that. I think when I stop enjoying that, if I can't produce, if I can't help a team, that's when I'll stop playing. Is that next year? Maybe it is. But I certainly want to keep playing."
Manning erased any doubts about his ability to bounce back from his neck problems last season when he threw for a then-franchise-record 37 touchdowns and had a league-best 68.6 completion percentage in his first season with the Broncos.
Followed that up with this season's record-breaking numbers, then outplayed archrival Tom Brady last week in the AFC Championship Game, throwing for 400 yards and two touchdowns. This isn't a guy who's hanging on. This isn't a guy on his last leg.
"You can just tell he still enjoys it," Broncos wide receiver Wes Welker said. "He loves being around the guys. He loves the game-planning. He loves Sundays. You can just tell that he still loves every aspect of the game. It's great to see."
So, how much longer will Manning play? One more year? Two more? Three more? His contract with the Broncos runs through 2016.
"That's a question for him," Welker said. "But he's had arguably the best year of his career this year. You really don't see him slowing down at all."
Said Elway: "I guarantee you if I was in his shoes I would [still] enjoy it. I'm sure he is still enjoying it, and he's on a good football team which, late in your career is so crucial."
Bottom line: He'll write the ending to his career when he's damn well ready. And that's not right now.
On Twitter: @Pdomo