Britain's Joe Calzaghe plans to fight for one more year before retiring.
Calzaghe is unbeaten in 43 fights
The 35-year-old will add the WBC and WBA belts to his WBO super middleweight title if he beats Mikkel Kessler at the Millennium Stadium on Saturday.
He told BBC One's Inside Sport: "I realise the end is near. I'm not going to be an Evander Holyfield and fight at 44, getting my head punched in.
"I'm giving myself a 12-month span to keep at the top and then I'll let it go. There'll be no comebacks."
Calzaghe is unbeaten in 43 fights but he admitted he is starting to feel his age.
"I realise I'm getting to that point in my career where you're not going to improve and you slowly decline, that's nature," he said.
"Is it getting easier? No way, it's not getting easier making the weight and everything, of course not.
"But I still believe I'm at my peak, I still believe I've got a lot to give, I still believe I've got great fights in me."
Calzaghe added he will have fulfilled all his ambitions if he overcomes unbeaten Dane Kessler in Cardiff.
The Welshman already holds the WBO belt and won the IBF title with victory over Jeff Lacy before relinquishing it a year ago.
"Winning this fight, I will add the WBC/WBA belt to my collection which means I have all four belts," he said.
"I'm Ring champion, what else could I possibly achieve?"