Years ago, when I worked as a hall tech. I'd mark certain parts that had intermittent errors, whenever I RMA'd them, so that when I got them back later, I would immediately know. Because it was SOP to replace parts until the PC worked (not every tech was particularly good at troubleshooting), parts would end up coming back pretty regularly, since there was often nothing wrong with them. But it was super frustrating to get back the motherboard you knew had a faulty dimm slot, only to see that dimm slot fail for another machine replacement.
