The short answer

Judge the movement and the case finish first, and treat the dial as the last checkpoint. On a replica IWC IW376073 the parts that decide whether the watch survives two years of regular wear are the chronograph movement, the pusher and crown action, and the quality of the case polishing and brushing. Dial print and hand shape matter, but they show up in photographs and are easy to compare. Movement behaviour does not show up in a still image, so ask for a short video of the chronograph starting, stopping and snapping back to zero, plus a macro shot of the caseback and the date window, before any money changes hands. If a seller cannot produce those three items, keep looking.

One more step comes before all of that: confirm which variant the listing is actually showing. Replica listings reuse reference numbers loosely, and the same reference can be offered with different dial colours, bracelet options and caseback engraving. Write down the exact configuration you expect, then check it against the seller's photos, not against the catalogue image at the top of the page.

What to look for

Movement and chronograph function

Most replicas in this reference class run a variant of the Valjoux 7750 architecture, usually an Asian-made copy, sometimes sold with a claim of a Swiss or Swiss-parts original. The architecture is robust and serviceable, but the quality of the assembled unit varies widely. Ask which movement is fitted, whether the rotor is decorated, and whether the subdial layout matches the genuine watch. A layout mismatch is the fastest tell, and no amount of case polishing hides it.

Test the chronograph before you accept the watch. The centre seconds hand should start with one firm push, stop cleanly, and fly back to twelve without hesitation or overshoot. Pushers should feel crisp with a short travel, not spongy or grinding. Wind the crown through twenty turns and listen for roughness. Set the time forward past midnight and back to check that the date flips at the right moment and that the quickset works.

Case, lugs and finishing

Look at brushing direction on the lugs and case flanks. Good finishing runs in one direction with even grain and no swirl marks left from a polishing wheel. Check the bevel along the lug edges: a sharp, consistent line reads as care, while a rounded, soft edge reads as cost cutting. Compare case thickness against the genuine specification. Chronograph movements add height, and a case that sits noticeably taller than the original is a compromise you should know about before ordering, not after.

Inspect the caseback engraving under angled light. Deep, crisp lettering with clean edges is what you want. Shallow laser etching looks grey and flat.

Dial, hands and lume

Request a macro photo of the dial. Check that applied indices sit level and flush, that printing is solid with no bleed at the edges, and that the date wheel font is correct for the reference. The date should sit centred in the window, not drifting toward one edge. Lume colour should read as a soft cream on vintage-styled dials and a clean white on modern ones; a bright synthetic green is a warning sign. Hand length should reach the minute track markers precisely.

Crystal and anti-reflective coating

The crystal should be sapphire, and the anti-reflective coating should be applied to the inside surface. Tilt the watch under a light: strong blue or purple reflection across the whole crystal usually means an external coating that will scratch off. A faint, almost invisible reflection is the better result.

Strap, bracelet and clasp

On a bracelet, check for solid end links that fit the case without gaps, screw-in pins rather than friction pins, and a clasp that closes with a firm click. Engraving on the clasp should be sharp. On a leather strap, stiff corrected-grain leather is common at the lower end; ask what the strap is made of if that matters to you.

Parameter bands to compare against the genuine watch

• Case diameter: expect a match within about half a millimetre of the published figure
• Case thickness: the most common discrepancy, often one to two millimetres over
• Lug width: should match the strap or bracelet size exactly, with no adapters
• Beat rate: 28,800 vibrations per hour on the 7750 family
• Power reserve: roughly 40 to 48 hours on a healthy unit
• Water resistance: treat any rating above splash resistance as unverified unless the case has been pressure tested
• Crystal: sapphire with internal anti-reflective coating

Pitfalls

• Stock catalogue photos used in place of pictures of the actual unit you will receive
• Claims of a genuine Swiss movement at a price that cannot support one
• No quality control photo set, or a refusal to send a video of the chronograph running
• Payment methods with no recourse if the watch arrives faulty
• Water resistance taken on trust, then a swim that ends the warranty argument
• Subdial layout or date position that does not match the reference you wanted
• Case thickness that only becomes obvious once the watch is on your wrist

FAQ

Is a Swiss movement claim worth paying more for?

Only if the seller can name the calibre and show it. Otherwise a well-assembled Asian 7750 copy is the safer purchase, because parts and servicing are easier to find and the price gap is large.

Should I run the chronograph often?

Run it briefly every few weeks to keep the mechanism exercised, then reset it fully. Leaving it engaged for long periods adds wear without benefit.

How do I check the date change?

Set the time to about 9 pm, then wind forward through midnight and watch the flip. Avoid using the quickset between roughly 9 pm and 3 am, when the mechanism is engaged.

Will it survive swimming?

Do not assume so. Gaskets on replica cases are not tested to the same standard, and a pressure test is the only way to know.

How long should it last?

A clean 7750-based unit with sensible use commonly runs for years before a service. Dust, moisture and knocks are the main threats, not the design.