Watch Buying Guide: Movements, Water Resistance & Strap Sizing

Movement types: automatic, quartz, and solar

The movement is the engine of the watch, and it's the single biggest factor in how a watch feels to own — not just how it tells time.

Automatic (self-winding mechanical) movements are powered entirely by the motion of your wrist, winding an internal mainspring as you move through the day. No battery, ever. In exchange for that mechanical charm, an automatic watch will typically run a few seconds fast or slow per day, and needs to be worn regularly (or kept on a watch winder) to stay powered. This is the movement collectors tend to gravitate toward, and it's what you're paying for in most of our Seiko Presage and premium Citizen pieces.

Quartz movements use a battery-powered oscillating crystal and are, practically speaking, the most accurate timekeeping technology in general use — typically accurate to within a few seconds per month. They're lower-maintenance (a battery swap every 1–2 years is the only real upkeep) and tend to cost less than an equivalent automatic. Nearly all Casio, Timex, and everyday Titan watches use quartz movements.

Solar (eco-drive / tough solar) movements are a variant of quartz that charge from any light source — sunlight or a room lamp — through a solar cell hidden under the dial. No battery replacement, ever, as long as the watch sees light regularly. Several Citizen Eco-Drive and Casio Tough Solar models we carry use this technology, and it's a strong choice if you want quartz-level accuracy with zero servicing.

Water resistance ratings: what they actually mean

Water-resistance figures are printed in metres or ATM (atmospheres), and the number is more conservative than it looks — it describes a controlled, static lab test, not real-world conditions like a moving wrist in the shower or the pressure change of a dive.

• 30m / 3 ATM — splash and rain resistant. Not safe for swimming, and not safe for the shower.
• 50m / 5 ATM — safe for swimming and brief water exposure, not for diving or high-pressure water (a strong shower jet counts).
• 100m / 10 ATM — safe for swimming, snorkelling, and most water sports.
• 200m / 20 ATM and above — genuine diving territory, built and tested for scuba use.

A rating is also not permanent — the seals and gaskets that keep water out age over time, especially on watches that are opened for battery changes. If a quartz watch is water resistant and due for a battery, we recommend having the case reseal-tested when the battery is replaced, which we do as a matter of course at our service counter.

Strap and bracelet sizing

Two numbers matter when fitting a strap: lug width and wrist size.

Lug width is the gap between the two horns on the case where the strap attaches, almost always printed on the case back or the original strap itself, typically between 16mm and 22mm. Any replacement strap needs to match this exactly — a strap that's 2mm off either way won't sit flush against the case.

For a metal bracelet, sizing is done by removing links using a small pin-and-punch tool — not by adjusting a buckle. This isn't something we'd recommend doing at home without the right tool, since a slipped punch can scratch the bracelet or damage the pin; our counter does this as a same-visit adjustment, free with any new bracelet-watch purchase.

For a leather or fabric strap, most come with 5–7 adjustment holes and fit a reasonable range of wrist sizes without alteration — if you're between holes, a strap can usually be shortened at the buckle end during service.

Not sure what you're working with? Bring the watch (or the strap) to any of our boutiques and we'll fit it while you wait.