One of the first thing an old hand told me in my first days on the job, in aerospace, was: If you have a part, but have no paper work you can match against the

One of the first thing an old hand told me in my first days on the job, in aerospace, was: If you have a part, but have no paper work you can match against the part that tells you what it is, you can throw the part away. So, never loose documentation. I took that to heart. Took a case of a switcheroo, mixing items that looked similar but aren't, to really drive the point home.