RE: [Demo notebook] QC clinic: photographic evidence and its limits · RWI-19445

Case 1 — Maintenance question: how do I tell if an automatic actually needs service?

Common advice says service every five years, but service is expensive and some people run watches much longer. What observable signs actually indicate a mechanical watch needs attention, as opposed to just being due on a calendar?

Exercise RWI-19445/1: address this question within its stated limits.