Mike Tyson, Evander Holyfield, Meldrick Taylor, Riddick Bowe, Julio Cesar Chavez, Terry Norris, James Toney, Michael Nunn and Simon Brown are among the best fighters of the past decade, and each has suffered a major setback.
And then there is Pernell Whitaker, whose reputation remains unsullied despite a highly controversial 12-round loss to Jose Ramirez in 1989 that momentarily robbed him of the lightweight title.
Whitaker, who will be seeking his sixth world crown against World Boxing Association junior middleweight champion Julio Cesar Vasquez in Atlantic City on Saturday, was asked how he has remained king of the hill while so many other superior fighters have fallen from the summit.
"You've got to love what you do, and I love to fight," he said. "You can't get up one morning and say, 'I don't want to train today.' It's your job. And the day I start liking boxing and not loving it, that's when I'll retire.
"I can get bored like everyone else," he said. "I've been fighting for 23 years, amateur and pro. If I feel I'm getting stale, I'll take a month off from the gym. But when I finally walk away, I'll take all my boxing gear down to the Salvation Army and never look back."
At 31, he remains focused.
"A lot of fighters get caught up in the financial side, and it robs them of their concentration," said Whitaker, who has had promoter Dan Duva and financial adviser Shelly Finkel in his corner since turning pro in 1984. "You have to be able to trust the judgment of the people handling your affairs and keep your mind on fighting."
Even the recent departure of George Benton, his longtime trainer and confidant who was fired by Duva in a contract squabble, has failed to distract Whitaker in his quest to win a title in a third different weight class.
"I can't take away what George has meant to me the last 10 years," he said. "He did a great job of teaching to get me to this point. But George has just passed the torch to Ronnie Shields, who has always been with me when I opened training camp. But at this point in my career, I know what I have to do in the ring. No one in my corner has to remind me."
For Whitaker, a masterful defense always has been his principal advantage, using his quick feet and lightning hands to frustrate stalking rivals. He said he does not bother to watch tapes of his opponents to plot strategy. He will fight his fight regardless of his rival's reputation.
"Honestly, I've never seen Vasquez fight," he said. "I don't sit home watching other guys fight. I just wait until I get in the ring. I don't change my style, but I adapt to what the other guy's doing."
After eliminating all the meaningful competition in the lightweight class, Whitaker moved up to 147 pounds in 1993 to challenge the then-unbeaten Chavez. Whitaker won convincingly in the eyes of everyone but two judges, and it ended in a draw. Chavez has avoided any talk of a rematch.
"It's clear that he doesn't want to fight me again, and I'm not going to chase him," Whitaker said.
Vasquez, a native of Argentina, is little known to American fight fans, but the fact that he owns a share of the 154-pound title is enough of an incentive for Whitaker.
"This is a project for me," Whitaker said. "I've really got nothing else to prove. But people are always looking for someone to test my chin. That's the excitement angle to this fight -- me stepping up in weight against a big puncher. It will bring out a crowd.
"I can punch, too. But punchers don't win fights; boxers do. And I'm a better distance fighter than anyone around today. The longer the fight goes, I'm getting fresher. That's the real secret to my still being at the top of my game."
It has been that way since Whitaker, with his elusive left-handed style, dazzled at the 1984 Olympic Games in Los Angeles.
"My focus in 1984 was just to win a gold medal for my mother," he said. "I wasn't really looking down the road to winning a lot of [professional] titles. I just thought, 'If it happens, it happens.' "
That was 11 years and five championships ago. The Salvation Army will just have to wait for his visit a trifle longer.