RE: Carbon Arrows Over Time
Yes, carbon arrows can weaken in spine over time, as well as warp or become bent at the tip. It all depends on how much you shoot them, what you shoot them into and how you remove them from targets. They also don't like to be left in the sunlight. Heat is a carbon arrows enemy, as is wiggling them back forth to get them out of a target.
The statement "They are either straight or broken" is one of the biggests myths and BS lines in archery. Some carbons are bad right out of the box if you get cheap enough ones.
I personally have never wore any out, but I have ruined a few and seen many others that have lost spine or warped.
While carbons may be more durable and less resistant to bending than aluminums you still need to take some care when using them. I would check them more often than you would an aluminum.
Paul