I bring this up because on Saturday night at the Barclays Center in Brooklyn, N.Y., ageless Philadelphia boxing legend Bernard "The Executioner" Hopkins will have his 63rd professional fight, spanning 25 years and touching parts of 4 decades.
Hopkins (52-6-2, with two no-contests) will fight undefeated Tavoris Cloud (24-0, 19 knockouts) for Cloud's International Boxing Federation light heavyweight championship.
I'll be interested to see how many fans will show up in Brooklyn to see whether Hopkins can win another title at age 48.
It's one thing for Hopkins, who defended the unified middleweight title for a record 20 times, to still be able to box after nearly a half century of life, but it's something different to find out whether fans still want to see it.
Hopkins might not be physically past his time, but we'll find out whether time has passed him by.
"Age is not an enemy to me," said Hopkins, who is fighting for the first time in nearly a year. "The clock is not something to try and stop.
"You can get the daylight to be earlier or the darkness to be later, but the clock has to move forward."
In a similar way, so does sports. Change is the unchallengeable force in everything.
Athletes get old and their skills deteriorate, and, at some point, even if they are able to stay in the game, they are not the performer people expect them to be.
At some point if you hang around long enough, the comparisons are no longer to your opponent, but mainly to your younger self.
That's where Hopkins is now.
The fact that Hopkins can still headline a fight card 2 years short of 50 speaks for itself, but what have we really seen? Or, more important, who is paying attention?
On May, 21, 2011, more than 17,000 fans saw then-46-year-old Hopkins defeat Jean Pascal to become the oldest man to win a boxing world title.
But the fight was in Pascal's hometown of Montreal, and the vast majority of the crowd was there in support of him and an undercard that featured six Canadian boxers.
Outside of two fights with Pascal in Canada and a Las Vegas fight in 2008 against Joe Calzaghe - who was credited with drawing a large number of Brits across the pond to cheer the Welshman - Hopkins' most recent fights have been modest draws at the gate.
The Barclays Center seats 19,000 for boxing, so it would be hard to disguise 11,000 empty seats.
While boxing may be referred to as the "sweet science," the most exciting part of the game, the part that really draws people's attention, is the knockout.
Just as baseball fans would rather see home runs than opposite-field singles, boxing fans would rather see a guy stretch an opponent out on the canvas than get a majority decision.
You don't anticipate a knockout in fights involving Hopkins anymore.
Hopkins has always been more of a technical boxer than a knockout fighter. He's a master at defense and counterpunching and has relied on those skills more and more as he's aged.
The last opponent Hopkins knocked out was Oscar De La Hoya, now his partner in Golden Boy Promotions, back in 2004.
Hopkins, who has never knocked out anyone in a fight above the middleweight class, hasn't displayed the ability to seriously hurt opponents since he turned 40, which is why he is a pedestrian 7-4-1 with a no-contest in 13 bouts during that time.
Guile, cunning and experience have helped Hopkins win or stay upright in fights way past an age when either seems humanly possible.
But that has not necessarily translated into interesting fights.
"Hopkins doesn't faze me," said Cloud, who won many of his first 19 fights by knockout but has only one in his last five. "I don't look at him as being physically formidable.
"He's all skills, mind games and trickery. He might have more tricks than me, but I'm going to throw punches. You have to throw punches to win fights."
If Cloud pushes the fight, he could make Hopkins uncomfortable enough to alter his game plan. Few have managed to do that.
"Who is going to run from a 48-year-old man?" Hopkins queried. "Cloud isn't going to run. He's going to fight. I'm going to be the professor and teach him his ABC's."
If this fight follows the pattern on most of Hopkins' post-40 fights, expect a lot of clutching and holding, resulting in a low-action fight that someone will win by a close decision.
Will people continue to watch Hopkins hold the heavens on his shoulders simply because he can? We'll find out on Saturday.