Hopkins is the grand pa of boxing but 36 is not exactly prime either. What age do you consider old for a boxer? Or is it not as simple as that? Do we add in when the boxer turned pro, how many fights they have had, how many hard fights and ring wars, amature career and competition, the style of fighter the boxer is and breaks in the career? Or just when a fighter has passed his peak? Some boxers arer made to look old over night and some seem to be able to keep putting in better performances as they go along. And if there is a magic number then should any acheivments be discredited from that point on?
Depends, there's no magical number. Joe is removed from his prime by about only 2-3 years, Hopkins at least 7 years.
When you've been in the game for longer than 5yrs ... you're practically old no matter your age. The fight game takes a tremendous toll on your body and mind. Morales and Barrera were both in their early 30's and both retired recently having atleast 13 years of experience.
different fighters age differently. a lot of factors cause fighters to become "old/faded/shot" such as # of years as a pro, type of fighting style, # of wars (if any), physical deterioration, mental deterioration etc...... also in regards to your last question, i feel that achievements should'nt be discredited once a fighter is past his best years. achievements are achievements. perhaps the degree to which they impact on a fighters overall career can be debated, but they should'nt be discredited.