They usually peak at around age 28-30, it really depends on the fighter though. Some boxers primes last longer than others because of the types of fights they're in, tough fights can take A LOT out of a fighter.
Fights that end up with both guys taking brutal beatings, or a guy getting KO'd can change a fighter forever. A perfect example is Fernando Vargas, he was a monster at age 22 but was in a brutal fight with Felix Trinidad, he was never the same after that, getting KO'd in multiple fights.
That is a question that no one can answer because every person is different. Just look at Roy Jones Jr and Bernard Hopkins . Age is a funny thing I think my prime was 16 years old man I was something else fast lol.
Depends certain factors like age they started fighting, number of fights and amount of wear and tear. In other words, it depends on a fighter's mileage. For instance, a fighter who turns pro at 18 would peak at around 30 years old. But fighters like Floyd Mayweather, who now fights once a year, are still peak even at age 36.
Age is not much of a factor as lifestyle, activity and proper training and handling as well as management of a professional boxer. There have been many who are athletically and naturally physically gifted as boxers but they don't even hit their prime because of poor life style, inactivity and poor management and training. And there have been cases of already aging fighters who almost miraculously went into transformation from club fighters/journeymen/gatekeepers to elite fighters or another career peaks on account of change in lifestyle and managers and trainers.Archie Moore is a classic example. Curtis Cokes, Bernard Hopkins, Freddie Pendleton are also fine specimens.
