Water Resistance in Watches: What Each Number Means

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What you really need to decide

Almost everyone starts by looking at prices and ends up making the wrong purchase. The correct approach is the reverse: first decide how you’re going to use it and how often, and only then look at the different models. Once you’ve clarified that, three or four specifications are enough to rule out 80 per cent of the range. This guide is all about exactly that: which details matter, which are just marketing hype, and how to translate them into a concrete purchasing decision.

Quartz, automatic or manual: which to choose and why

The quartz It is the most accurate and the most practical: it diverts around ±15 seconds per month, it needs nothing more than a new battery every 2–4 years and is more shock-resistant. The automatic It is powered by a wrist movement and deflects between -10 and +30 seconds a day (a COSC-certified calibre has a rate of between -4 and +6), but it is the one with a mechanical soul, a sliding seconds hand and long-term value. The manual It needs to be wound every day and is usually more delicate, which is why it’s used in dress watches. If you’re looking for accuracy, go for quartz; if you’re looking for fine watchmaking, go for an automatic.

Bezel: why the diving bezel only rotates in one direction

The rotating bezel on a diving watch is unidirectional For safety reasons: it can only move anti-clockwise, so that if you bump into it by accident, it can only shorten the calculated dive time, never extend it. That of a GMT is bidirectional and features 24 markings for reading a second time zone. The tachometer A chronograph allows you to calculate your average speed over a kilometre. And on a dress watch, a slim, polished bezel is what makes the case appear smaller and more elegant than it actually is.

Value and depreciation: which watches hold their value

Almost all watches are an expense, not an investment, and it’s best to buy them with that in mind. That said, there are clear patterns: models from brands with a rich history and limited production runs retain their value better on the second-hand market, whilst fashion brands lose between a 60 and 80 per cent as soon as they leave the shop. Affordable watches with an established reputation (the classics from Seiko, Casio or Orient) rarely fall much below the initial price range because their starting price is already low. The paperwork, the box and the condition of the strap affect the selling price more than people realise.

Steel, titanium and coatings

The standard is the 316L steel, surgical grade, corrosion-resistant and easy to polish. The 904L (which Rolex calls Oystersteel) is slightly more corrosion-resistant and produces a denser polish, but the difference in everyday use is minimal. The titanium It weighs 40 per cent less and is hypoallergenic, making it ideal if you find the weight a problem, although it does show wear more easily. Regarding coatings: the PVD It is a thin layer that eventually wears away at the edges, whilst the DLC It is much harder and lasts for years. The gold plating on cheaper watches usually lasts between 2 and 5 years of daily use.

• Quality of materials and finishes
• Recent verified reviews (including 3–4-star reviews)
• Warranty and returns policy
• Current price compared with its historical average
• Seller's reputation
• Make sure the key features suit your needs (day-to-day use)

Which watch is right for each occasion?

The classic rule still holds true: the more formal the occasion, the more understated and simple the watch should be. For suit, a 36–40 mm case, a slim profile that fits under the wrist, a clean dial and a leather strap. For office and diary, an elegant sports watch measuring 38–41 mm with a steel bracelet covers all the bases. For sport and water, a 200-metre diver’s watch or a rugged digital watch. And for to travel, a GMT watch lets you keep track of two time zones at a glance. If you’re only going to own one watch, a 39–40 mm three-hand model with 10 ATM water resistance and an interchangeable bracelet is the most versatile option available.

Criterion	Seiko Presage CocktailOur choice	Orient Bambino V2
Ideal for	Balanced and general use	Day-to-Day Life
Strength	Value for money	Specific features
Approximate price	from around €80	from around €50
Recommendation	Our choice	Best alternative
View on Amazon	See price →	See price →

Luminescence: Super-LumiNova and LumiBrite

Modern luminescent paint is not radioactive: it is a phosphorescent material that absorbs light and gradually releases it. Super-LumiNova (Switzerland) and LumiBrite (Seiko) are the models, with variants such as the bluish BGW9 or the greenish C3, which is the one that shines the brightest. What makes the difference in practice is not the paint brand but the layer thickness: that’s why a €150 Seiko can outshine a €1,500 Swiss watch. With diving watches, check that the bezel at 12 o’clock and the minute hand – which is the one that counts underwater – are also luminescent.

How to buy a watch without being ripped off

Four things to check before paying: that the salesperson whether it is the manufacturer or an authorised distributor (on marketplaces, check who is shipping the item and who is invoicing); that the warranty that it is the brand’s official specification in Spain and not just that of the seller; that the specifications advertised match the official profile from the manufacturer, particularly crystal and ATM models, as these are where claims are most often exaggerated; and ensure the price isn’t significantly below market value, which is a common sign of a replica. Keep the box, paperwork and receipt: with watches, these add to the value should you ever sell it.

Glossary: the terms you’ll see in the fact sheets

Lug to lug

The distance between the ends of the lugs. This determines how the watch sits on the wrist.

Power reserve

The number of hours a mechanical watch continues to run without being wound or set in motion.

Hacking

A function that stops the seconds hand when the crown is pulled out, to synchronise to the second.

ISO 6425

A standard certifying a watch as suitable for diving. It is marked ‘DIVER’S’ on the dial.

Alternations

Vibrations per hour of the movement (21,600 or 28,800 are the most common).

Fine-tuning

A clasp system that allows the size of the bracelet to be adjusted in small increments.

Super-LumiNova

Non-radioactive phosphorescent paint that absorbs light and glows in the dark.

Conclusion: the three-step decision-making process

In a nutshell: work out what you’ll actually use it for, narrow it down to the two or three features that really matter to you, and tailor your budget accordingly. With that in mind, the Seiko Presage Cocktail is the default choice, and the Orient Bambino V2 is the alternative if your priorities lie elsewhere. Everything else — extra features, promotions, high-end models — is secondary if those three steps are sorted out properly.

Frequently Asked Questions

By the Watch Guide Team · reviewed by

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