I have a Buck 110 from 1970. I carried it everywhere and used it for things you wouldn;t even use a knife for. Stopped carrying it in 1996 when I got my BM. It is still solid (literally) as a rock. The blade might cut through paper if you followed the scoreline with a good pair of scissors... but it still locks and looks good.
I have a BM-Emerson 975 that I've been carrying every day, without fail, since 02/96. I've inertia snapped it 54.269 skabillion times and it'll still flick open with my thumbnail... just as fast as an auto. At lockup there is less than zero play (is that possible?). The blade at the tanto end has a tiny chip, the tip is bent 1 billionth of a millimeter, and, up until a few days ago when I got my (still questionable) Sharpmaker, it was duller than a sapling branch. But now, despite my sloppy beginner skills with the Sharpmaker, it'll at least cut through fog. Tomorrow it's going out in the mail to BM for some R&R and lifesharp service.
I've got two SPydies that see very littlle carry and an assortment of cheapos.... none of which have been used/carried enough that I can attest to their reliability.