An anonymous reader writes "Anyone who's worked in a large engineering firm is familiar with institutional amnesia. Things get built, and then forgotten. Documentation is supposed to help, but rots, is lost, or uses obsolete methods and notation nobody understands anymore. I recently found myself in a strange position, rehired as a consultant with the unofficial job of reminding the company how an old plant works. I even have some personal copies of documents they seem to have lost, which I have to awkwardly smuggle back in. I don't find these kinds of experience written about often, but I'm convinced they're more common than you'd think."