safety of carbon fiber bonded to aluminum fork crown I recently experienced the failure of the carbon fork on my 2001 K2 Mod3 road bike at 20 miles per hour. Yes, I was injured. My question is the bonding agent that secures the carbon fiber fork to the aluminum fork as strong and durable as the carbon fiber or the aluminum. Also I have been told by a bicycle manufacturer that the workable lifespan of "high performance bikes to be less than 10yrs, which seems to not agree with the article on lifespan of carbon fiber bikes that gives them an unlimited lifespan. I have some concern because I like to purchase my bikes slightly used thinking I can afford a much nicer bike. Example, I just purchased a Serotta Legend Ti with carbon forks &amp; seat stays, hardly used for $3000 but am now somewhat nervous about material failure. Whats one to do to know if a bike is safe?
Carbon fiber is a bit tougher to determine the safety of than steel or aluminum (where a thorough visual inspection normally reveals the serious flaws, along with checks of headset tightness and what not) - aside from a thorough visual inspection for cracks and damage all around, you really need a professional evaluation. Bikeradar has some tips for inspecting carbon fiber bikes - key points are bonding areas and essentially places where stress builds up and making sure the bike hasn't been crashed before. There are plenty of guides on buying used bicycles online and safety checks to perform on them. 

As for lifetime, especially in the case of a high end carbon fiber bike, the lifetime is a function of how much it has been used. A crash can do a lot more damage to a high end carbon fiber bike than to a lower end steel/aluminum bike (due to likely higher speeds and weight savings). There was a previous question here which highlighted the lifetime of carbon fiber bikes (especially forks), which you should read. In particular, the article by Zinn is useful.