Packaged with the handlebar stem for the recent bar-and-stem change I did on a customer's titanium Serotta was a thick, black booklet with the word "WARNING" in distinctly unfriendly letters on the cover. When I photographed it I noticed that camera motion had given the images a nice jangly, alarming look, so I made a collage of a sequence of them.
Inside the black cover was the same information in about 27 languages. There was about a page and a half of fine print covering all the ways you could mangle or kill yourself, and about three-quarters of a page of warranty information.
The makers of the carbon fiber handlebar took a more low-key, upbeat approach. You had to pay attention to see them tell you that the bars you just paid $250 (US) for should be replaced every three years. If you race a full season on them, they should be replaced after one year.
To be fair, even in the days of aluminum alloy the manufacturers recommended replacement every three years. After about 17 years I started to wonder about my old Cinellis when they started to creak a tiny bit, so I swapped them out for a new pair. I've been running those for probably a dozen years now.
No manufacturer wants to take a chance and recommend a customer grind their product down to a nub. They'll gladly use the story of such long-term endurance in their advertising, but it's never official policy.
When you're talking about a material like carbon fiber, known to fail abruptly when it finally goes, you may want to abide more closely by the manufacturer's recommendation.
