Knowledge base
The bits nobody explains properly
A growing reference for watch geeks — movements, sizing, water resistance, materials and servicing, written in plain English and free of marketing gloss. Tap any topic to expand it.
Sizing & fit
Water resistance
Dials, crystals & lume
Service & care
Glossary
Quick answers
- How accurate should a mechanical watch be?
- Most modern automatics run between -10 and +10 seconds a day depending on position and wear. Consistency matters more than the raw number: a watch that gains a steady five seconds a day is healthier than one that swings unpredictably.
- Do I need to service every five years?
- Five years is a manufacturer's default, not a rule. Many movements run well for eight to ten years. Service when timekeeping drifts noticeably, the power reserve drops, the winding feels gritty, or before you expose the watch to water.
- Which size actually fits a 6.5" wrist?
- Look at lug-to-lug rather than diameter. Under about 47mm lug-to-lug will sit flat on a 6.5-inch wrist; a 38-40mm case in that range usually wears comfortably.
- Can I swim with a 100m watch?
- Yes for pool and surface swimming, assuming the gaskets and crown are in good order. Leave diving, and hot showers, to a 200m watch with a screw-down crown that has been pressure tested recently.