Most guides to buying a modded watch are really catalogues with paragraphs around them. This one is a checklist you can use on any seller, including us.
Start with the movement, then stop thinking about it
Confirm it is a Seiko NH-family calibre — NH35, NH36, NH34 or NH38 — and that the listing says which one. After that, the movement is settled: they share the same specifications, so the calibre tells you what the dial displays and nothing about quality. The detail is in the comparison guide.
If a listing will not say what movement is inside, that is the end of the conversation. It is the single most basic disclosure in this category.
The four specifications that actually change the watch
Crystal
You want sapphire. It resists scratches in ordinary life; mineral glass does not, and hardened mineral is a marketing term for mineral. Ask whether it has an anti-reflective coating, and on which side — internal AR keeps the coating out of harm's way while still cutting glare.
Case steel
316L stainless is the baseline for a watch you intend to wear often. It handles sweat and salt without pitting. Some builders use 904L; it is marginally more corrosion-resistant and mostly a talking point. What matters more is the finishing — whether brushed surfaces are even and the transition to polished edges is crisp.
Bezel insert
Ceramic holds its finish almost indefinitely. Aluminium fades and scuffs, which some people actively want for a vintage look. Sapphire inserts exist and look superb. Any of these is a legitimate choice — just know which one you are getting.
Bracelet
Ask about solid end links and a screwed or solid-pin construction. Hollow end links rattle and are the single most common giveaway of a cheap build. The clasp matters too: a stamped clasp on an otherwise good watch feels wrong every time you put it on.
The water resistance question
This deserves its own section because it is where the most misleading claims live.
A case may be rated to 100 or 200 metres by whoever made the case. That rating applied to a sealed, tested assembly. Your mod was opened to fit a different dial, hands and movement — so the only question that matters is: were the gaskets replaced, and was the finished watch pressure-tested?
Ask it directly. A clear yes, ideally with the tested figure, is reassuring. A vague answer, or a listing that repeats the case's nominal rating without mentioning testing, means you should treat the watch as splash-resistant: fine in rain, fine washing your hands, not for swimming or showering.
Five questions to ask before you pay
- Which exact movement is in this watch?
- Is the crystal sapphire, and is it AR-coated?
- Was the case pressure-tested after assembly, and to what figure?
- What does the warranty cover, for how long, and who honours it? A mod carries no Seiko warranty — the builder's own warranty is the only one that exists.
- Are the photos of this watch, or of a representative build? Both are acceptable. Being told the wrong one is not.
Warning signs
- Luxury brand names used to describe the watch. A mod is not a product of any luxury house, is not affiliated with one, and should never be described using one's model names or trademarks. A seller who blurs this is either confused about what they are selling or hoping you will be.
- "Investment" framing. Mods have essentially no resale market. Anyone implying otherwise is not being straight with you.
- Only stock or rendered images, with no real photographs of an assembled watch.
- No stated service or warranty path. Movements need servicing eventually. You want to know who to contact.
- Unexplained alignment in photos — a bezel pip off centre, a chapter ring rotated, a date not centred in its window. These are assembly errors and they do not improve after delivery.
Sizing, briefly
Case diameter matters less than lug-to-lug, which determines whether the watch actually sits on your wrist or overhangs it. As a rough guide, keep lug-to-lug under about 47mm for wrists up to 17cm, and under about 50mm up to 19cm. Thickness is the other overlooked number — anything past 14mm will catch on a shirt cuff, and most automatic divers are past it.
Finally: buy the one you keep looking at
Once the specifications above check out, the remaining decision is entirely aesthetic, and your instinct is a better guide than any spec sheet. The watch you keep scrolling back to is the one you will actually wear.
If you want to apply this checklist to our builds, the full catalogue is here, and the women's collection covers the smaller case sizes. Every listing states the movement, case material and crystal — which is the standard we think you should hold every seller to.