It's not reasonable for my users to repair much of the stuff we make. It takes a rack full of test gear and software to test and calibrate most of it. The parts are often exotic. Replacing a chip-scale package or a BGA is not easy.
Once in a while we get a call from England or somewhere, with a problem, often an NMR product. We talk to them and sometimes give them advice, or send them a part, usually for free. I did that for a guy at Oxford University recently. Our OEM wouldn't repair it and wanted $60K for a new one. It had a bad power resistor, and we told him how to fix it. That cost us about $12K.