After 32,000 folds, iPhone Duo’s hinge serves up a big surprise

A new video review from Joanna Stern is drawing attention to the hinge on the iPhone Duo. Stern built a custom tool to fold the device automatically, then measured how the hinge held up after four nights of nonstop folding. According to Cult of Mac, the test reached 32,000 folds and ended with a big surprise.

Why the Hinge Is the Make-or-Break Component

On any foldable or dual-screen device, the hinge is the part people worry about most. It has to move thousands of times while keeping the device stable, aligned, and comfortable to use. A weak hinge can ruin an otherwise great product.

That is why durability tests like this one matter. Spec sheets and marketing claims can only say so much, and a repeatable, mechanical test shows how a device behaves after months or years of real use compressed into a few days.

A Custom-Built Tool for Automatic Folding

Stern didn't rely on a casual fold-it-by-hand approach. Her video review shows a custom-built tool that opened and closed the device automatically, night after night, with no tired wrists or inconsistent motion.

A machine applies the same motion every time, which makes the results easier to trust. It also let the test run while Stern was away, so a long endurance run could fit into a normal week.

Four Nights Add Up to 32,000 Folds

The headline number comes from running the tool over four nights. At that pace, the device was folded and unfolded roughly 32,000 times, far more than most people would manage in a normal ownership cycle.

If you fold a phone a hundred times a day, 32,000 folds is close to a full year of use. That makes the test a useful stress check for anyone wondering whether the hinge will last.

What Measuring the Hinge Actually Tells Us

The review focuses on measuring the hinge rather than just declaring that it survived. Tracking changes over time shows whether wear is gradual, sudden, or barely noticeable.

Looseness, stiffness, creaking, and misalignment can all develop long before a hinge fails outright. Measuring them gives a fuller picture of how the device would feel to own after heavy use.

The Surprise Cult of Mac Is Pointing To

Cult of Mac's headline says the hinge "serves up a big surprise," and the outcome is best seen in Stern's own video. This article won't try to paraphrase specific results beyond what the report describes.

What is clear is that the result was unexpected enough to make the headline. For a product category where durability fears run high, that alone makes the video worth watching.

How This Test Fits Into Foldable Durability Concerns

Durability has been one of the biggest questions around folding devices since they first appeared. Buyers have asked whether screens crease, hinges loosen, or dust and debris cause problems over time.

Independent testing helps answer those questions. When a reviewer with a track record of careful tech testing runs an endurance experiment, it adds useful evidence to a conversation that has often relied on anecdotes.

Why Joanna Stern's Reviews Carry Weight

Stern is known for creative, hands-on testing that goes beyond a typical first-impressions review. Her videos often mix humor with practical experiments, which makes technical results easy to follow.

The custom folding tool continues that approach. It turns a vague worry about whether a hinge will last into something viewers can see and judge for themselves.

What Potential Buyers Should Take Away

For anyone considering the iPhone Duo, the main lesson is that long-term hinge Performance can now be judged with real data. A test of this scale is more reassuring than a short hands-on session, though it can't replicate every real-world condition like pocket lint, drops, or temperature swings.

Shoppers should treat the result as one important data point alongside other reviews, warranty terms, and personal usage habits. It should shape expectations, but it isn't a guarantee.

The Bigger Picture for Apple Fans and Beyond

Whatever your view of folding devices, this kind of testing raises the bar for the whole category. Manufacturers know that reviewers can and will put hinges through punishing routines.

If you want the full story, watch Joanna Stern's video review and read Cult of Mac's coverage. Seeing the tool in action and hearing the findings directly is the best way to understand just how big this surprise really is.

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