How long is the average career span of a professional boxer?

http://bjsm.bmj.com/content/39/9/661.abstract

Subjects: Professional boxers in the United Kingdom and Australia.

Results: Since the 1930s, the average duration of a professional boxer’s career has dropped from 19 years to five years, and the mean number of career bouts has reduced from 336 to 13. This is despite no significant decline in participation rates from 1931 until 2002.

 

There's really no answer for that. Morales was not the same when he was in his late 20s. Fighters like Marquez age well. It really depends on the fighter.

When to retire is the one that really gets complicated. You want to retire on a good note, a winning streak. People would accuse you of ducking fighters. But when you retire after bad losses in a row, people would say "you should've retired a long time ago."

 

Those numbers don't count - they're not from the United States. Over here boxers don't know when to hang them up.