I’ve got a 2010 Cannondale Synapse Carbon 4 with 53,000 miles on it, and it’s still going strong. I’ve ridden every surface in New England except (obviously) snow. Including lots of lousy pavement, gravel, and even the (very) occasional single track. The only issue are cosmetic where bits of the clear coat are flaking. The resin underneath is fine.
One caution for carbon is crushing or impact forces, especially as you get lighter and more racy. Tube walls get thinner, and more susceptible to crushing or hard side impacts. It’s not a reason to baby the frame, just be aware of things like work stand clamps (don’t clamp the frame), and dropping heavy things on a frame in the car.
As was mentioned in a previous post, carbon is very repairable. A friend of mine crashed his Dogma and wound up with a hole in the down tube (we think it was another bike’s pedal that penetrated, but aren’t sure). He had it fixed, and the repair is invisible, and has no noticeable difference in performance.