Most buyers do give the prop a good visual inspection, at least from the spinner outward. That’s important, and it can reveal nicks and perhaps some cracks or a bad paint job.
What else is there to consider? The answer depends on the prop’s construction. Is it wood, metal, or composite? Fixed, variable-pitch, or ground adjustable?
Generally speaking, fixed pitch is the easiest propeller to inspect. It is one piece; there are no moving parts. Variable pitch propellers are more complex. With so many moving parts, there are many more things that can present themselves as problems.
In short terms, the simpler and newer the prop, the less we should expect to be troublesome. The converse is true, too. The older or more complex the prop, the closer the look we should give it.