Buying Used Parts

Linus and Jayz put out a couple of videos in the last week on the topic of buying used parts—I haven't watched them yet. My inexpert self would be very leery of going this route, assuming it's not a local known or otherwise trusted source—maybe a case, and some $20-30 items going for $5 where the risk is small.

What do you builders think?

View: https://www.youtube.com/watch?v=wl2IugfRMDk


View: https://www.youtube.com/watch?v=RKTlTya0Gm0
Haven't watched the vids yet but unless I knew the history of said components there's no way I'm purchasing used. With that said the used PC component market is popular in eastern Europe and Asia.