Some CF frames will last just fine even with a lot of abuse. I have an 1999 Trek 5000 OCLV that I've taken up and down fire roads around here and other places plenty of times, and it's holding up just fine. I've been through a couple of bottom brackets, a few headsets, a few sets of wheels, and the cranks are perceptibly worn in spots from rubbing my shoes. The frame is holding up just fine. A guy at work who parks his bike near mine rides an old lugged-tube style Trek CF bike (3300?) that he bought used. His is much older than mine and is in good shape as well.

I've also broken a couple of steel frames racing, and seen a few more steel frames broken racing. It used to be that you could get tubes replaced in a steel frame pretty cheaply, but there are fewer and fewer framebuilders around to do it. I've seen CF bikes go down hard in races and come back up fine (the look 496 and 596 track bikes, in particular), and others disintegrate (a couple of BMC track machines). I've crashed my Giant TCR track frame pretty hard and it's fine-- a couple of chips out of the clearcoat that were easily filled. I crashed into the back of my Specialized Langster Pro at full speed in a madison (aluminum, it belonged to someone else at the time) and it's fine, too. I use it as a TT frame so I don't have to change setups. I think at this point all my steel frames mostly just hang on the wall.