We Put Apple's iPhone Duo Through HELL. Here’s What Happened.

Joanna Stern's iPhone Duo review is the launch video most focused on whether the hinge lasts, and the answer after four nights of machine folding is that it held up. She also calls the Duo one of the most early-adopter Apple products she has tested. The 16-minute video went up on Oct 21, 2026, after a week with the phone.

What the video found

The centerpiece is a folding robot built by hardware designer Aaron Cohen, which opened and closed a Duo more than 32,000 times over four nights. A calibrated push-pull gauge measured the force needed to open the hinge before and after. Afterward the hinge was slightly stiffer, not looser, and Stern couldn't feel any difference in normal use. Her line: "after 32,000 folds, it felt pretty much the same as day one."

That's a meaningful result, but a limited one. It's one phone, and Stern points out that little is known about how Apple tests the hinge, while Samsung has said the Galaxy Z Fold 6 was rated for 200,000 folds. She also started a separate auto-clicker test on the inner screen, with results still to come at the time of the video.

Outside the hinge, her findings line up with most reviews. On the Hudson River, the matte inner screen cut reflections far better than the glossy Galaxy Z Fold 8, though the Samsung felt much lighter. The crease is still there, she says, just better hidden than Samsung's. Fingerprints were harder to wipe off the matte finish than a glossy one; see how to clean the inner screen.

The rest is a list of compromises. The camera behind the inner screen is fine for FaceTime in good light and poor elsewhere. There's no telephoto lens. The back got noticeably warm during photos, FaceTime and some apps, which Apple told her is the thermal design moving heat away from the chip. The volume buttons on top were hard to find by feel on calls, and Touch ID kept failing her even with five fingers enrolled; letting an Apple Watch unlock the phone helped. Battery got her through a full day, with less left at bedtime than her iPhone 18 Pro.

Her wish list for a second generation is a lighter body, Face ID, a better camera with a telephoto, a lower price and less heat. Most of her other frustrations, she says, are fixable with software updates and developers adapting their apps.

How it compares with other reviews

Stern's hinge result is more reassuring than JerryRigEverything's bend and dust test, but the two measure different things: repeated normal folding versus abuse the phone isn't designed for. Her warmth and camera complaints match The Verge's, and her Touch ID frustration matches Marques Brownlee's.

What it doesn't cover

Four nights of folding is a fraction of a phone's life. MacRumors also reports that the Duo wore a case during the test and that the robot didn't fully close it on every fold. And the test doesn't touch the inner-screen failures some owners have reported since launch. iFixit looks at those in its teardown, and our teardown roundup sums up what's known. Stern also gives no lab battery figures. The video includes a sponsored segment for DeleteMe.

More on this topic

For what a normal crease looks like and when to worry, see the crease explainer and how to protect the crease. Apple's $129 Folio and $79 case, both of which she tries, are covered in Apple's iPhone Duo Case and the best cases roundup.