The only camera failures I've encountered were with 3 different Goodwill finds. A Canon AF35M which exposes about a stop too hot but is otherwise fully functional; a Minolta AF2-M with a weak motor which can't wind on past about frame 15-20; and a Ricoh XR-2 which had a jammed shutter and dead meter, both of which I got working but the shutter turned out to be capping at higher speeds due to oil on the blades and jammed again after a couple of rolls.

I can forgive the Canon because the overexposing meter is an easy problem to work around.

I can't forgive the Minolta. I'd take another just like it, perhaps, but this particular example is unforgiven for its failing. I like everything about it as a simple P&S camera goes and shot some nice frames with it, but I can't cope with the flaky wind-on.

The Ricoh I can forgive, but only because it failed again quickly enough that I hadn't committed to buying any lenses for it, and because it came with a nice M42 mount Mamiya 55mm f/1.4 on an adapter. Sadly not the official Pentax adapter, just a cheap knock-off.