fighters actually used to spar less because they fought more. do the math. if you have a fight every 2-4 weeks, your sparring schedule alters drastically compared to a fighter that has a schedule of 3-6 months per fight. some fighters would spar 1 or 2 sessions between fights because that was really all they had to do to stay sharp, the more active you remain, the less polishing you need. fighting only once every 6 months will put some fighters between 80-100 rounds of hard sparring...in certain cities that hard sparring is more akin to a fight, in a lot of cases more damaging than a fight because the head gear gives people a false sense of security. furthermore, the damage of sparring is increased because there is no size regulations. anyone that attends a real boxing gym knows that sparring goes on between anyone and everyone of all weight classes because you take what you can get a lot of times. i've sparred lightweights to heavyweights and i weight between 152-158 at any given time. thats just the nature of the beast...go to philly and ask anyone in the fight community what the gym wars did to many promising careers.

i read fraziers book awhile back and thought it was a good start-up for interested people. sparring is without a doubt the most important element of a boxers training program. there is no other way to put it and any assumption otherwise would be foolish. but if you go to a gym and spar for 12 rounds 6 days a week instead of mixing in mitts and shadowboxing and double end bags and all the other tools of the trade, you are gonna be in a world of hurt...

bottom line: sparring is, in the same sense that mma is "safer" than boxing, more dangerous than actual matches. the reason for this is because in sparring you take a lot more punches in most cases because "you can"...headgear and puffy gloves do that to peoples confidence, including my own sometimes. if you are sparring 80 rounds for a 12 round title fight, then you need to take that into account, but no one ever does except doctors when they are diagnosing brain trauma post-career...and that, my friend, is how sparring shortens ring life. you said "back in the day when fighters sparred a lot more..." they didnt...they sparred less, they fought more, and their careers were indicative of such behavior...there has never been more sparring than there is now because as the distance between fights at all levels increases, it becomes more necessary.