Changing a Watch Battery: When to Do It Yourself and When Not To

What makes the difference

Most problems don’t stem from the product itself, but from how it’s used. Here’s what really makes a difference, listed in order of impact, along with specific steps and the mistakes that are made time and time again. No generic advice here: just things you can put into practice today and see the results tomorrow.

Straps and bracelets: the most cost-effective change

Changing the strap transforms a watch for €20–40 and is the best value-for-money upgrade there is. Measure the width between antlers (18, 20 and 22 mm are the most common) and choose according to your needs: steel for everyday use, skin for washing (never with water), rubber or FKM for sport and summer, and NATO made of nylon for a military look and quick changes. Look for pins made of quick release (quick-release) so that no tools are required. With steel bracelets, the detail that sets the good ones apart from the mediocre ones is the micro-adjustable fastening, which allows you to fine-tune the fit when your wrist swells in the heat.

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 is the brand’s official one and not just the seller’s; 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.

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.

The gauges that are actually inside

Almost all automatic cars costing less than €500 are fitted with one of these engines: Seiko NH35/4R35 (reliable, hackable, 41-hour power reserve, the standard for affordable watches), Miyota 8215 (cheap, second hand with a slight wobble) or Miyota 9015 (finer and at 28,800 alternations). Moving up, we find the ETA 2824-2 and its equivalent Sellita SW200, and the Powermatic 80 by Tissot, which stands out for its 80-hour power reserve. Knowing the calibre tells you more about the watch than the brand: two watches with very different price tags may share the same movement.

• 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)

Case size: the important figure is not the diameter

Everyone looks at the diameter in millimetres, but the person who decides whether a watch suits you is the lug to lug, the distance between the lugs. Rule of thumb: for a 16–17 cm wrist, look for a lug-to-lug measurement of just under 48 mm; up to 50–52 mm if your wrist is over 18 cm in diameter, 36–38 mm It is the classic style and the one that works best on a slender wrist or with a suit, 39–41 mm It’s the most versatile size available today, and anything over 44 mm takes you into the sports watch territory. A 40 mm watch with long, curved lugs looks better on the wrist than a 38 mm one with straight lugs.

Criterion	Hamilton Khaki Field MechanicalOur choice	Casio Edifice EQB-1200
Ideal for	Balanced and general use	Day-to-Day Life
Strength	Value for money	Specific features
Reviews	Very positive and numerous	Positive
Approximate price	from around €160	from around €100
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.

To conclude

Start by applying the advice above – that’s what makes the biggest difference – and leave the rest until you’ve got some experience under your belt. If, after doing this, you still haven’t got what you’re looking for, then it does make sense to change your watch: the Hamilton Khaki Field Mechanical is the most balanced option for making the leap, with the Casio Edifice EQB-1200 as an alternative.

Frequently Asked Questions

Is a quartz watch or an automatic watch better?

For accuracy and peace of mind, choose a quartz watch: ±15 seconds a month and a battery change every 2–4 years. For long-term value, choose a mechanical watch with a sliding seconds hand and automatic winding, with a tolerance of between –10 and +30 seconds a day and a service every 5–8 years.

Can I have a shower whilst wearing a 5 ATM watch?

It’s not advisable. Five atmospheres is measured under static conditions, and the shower jet generates higher pressure peaks; what’s more, the heat causes the seals to expand. For worry-free use with water, you need 10 ATM, and 20 ATM if you’re going diving.

Is sapphire glass worth it?

Yes, if the watch is going to be worn every day: with a hardness of 9 on the Mohs scale, it’s practically scratch-proof in everyday use, whereas mineral glass can be marked by sand or keys. The only advantage of mineral glass is that it absorbs a strong impact better without shattering.

Will an automatic car break down if I leave it standing?

No. Leaving it switched off won’t damage the mechanism; you’ll just need to set the time when you use it again. What it does need over the years is a service, every 5–8 years depending on use.

What width of strap do I need?

Check the distance between the lugs: 18, 20 and 22 mm will fit most watches. If your watch allows it, look for quick-release pins so you can change the strap without tools.

Should I go for the Hamilton Khaki Field Mechanical or the Casio Edifice EQB-1200?

The Hamilton Khaki Field Mechanical is the most well-rounded option and our default recommendation. The Casio Edifice EQB-1200 is a sensible choice if your priority is everyday wear. As a guide for your budget, the useful price range starts at around €100, and the best value is usually found at around €160.

By the Watch Guide Team · reviewed by

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