RE: [Demo notebook] Collector’s comparison desk: dimensions, fit and documented differences · RWI-20966

Case 28 — Maintenance question: how do I tell if an automatic actually needs service?

The calendar interval is a conservative default, not a rule. Useful signs, in rough order of seriousness: power reserve noticeably shorter than spec from full wind, rate drifting outside its usual range, the watch stopping on the wrist, gritty or rough winding, and the date changing slowly or late.