Unca_Sam

Buying any used bike is a risk. Steel bikes rust, bend, dent, and sometimes crack, aluminum bikes fatigue, dent, bend, and sometimes crack, and carbon fiber bikes...sometimes crack. It's the reason I try to inspect bikes before buying. The paint on the bike indicates that it was ridden, but probably cared for as well. Most of the components look good, with the small scrapes on the RD and the right integrated shifter being fair instead. If the owner or a mechanic dropped a tool on the top tube, it'd result in a small paint chip like that. The good news is that the chip is very small, and may not even be through the primer. The scuff on the stem is probably from a computer mount, while the stem cap scratches probably came from flipping the bike upside down on the ground for a roadside repair (which is annoyingly common).

There are other, additional areas to inspect for a carbon frame that we can't see. Depending on the construction, the dropouts could be aluminum bonded to the frame (I'm not familiar with the construction of this bike, consult with Trek's back catalogs if it's using bonded dropouts or integrated carbon dropouts). If they separate, that's the end of the frame. A sucked chain or a chain dropped to the inside of the cranks can be fatal for the frame, as carbon fiber is cut very easily that way. The thing is, few of these problems are without a similar issue on a steel or aluminum or titanium frame.