iPhone Duo hinge shows wear after 450,000 folds in CNET test

What the test has found so far

CNET has been folding an iPhone Duo on a livestream for three weeks, and the phone has now passed more than 451,000 folds. According to MacRumors, the hinge is showing clear signs of wear, although the device itself still works.

CNET says the hinge began to feel looser at around 390,000 folds. By 440,300 folds, the mechanism had shifted enough that the screen no longer opened fully before the folding machine closed it again, and the familiar snap was missing.

The screen now stops 5 to 10 degrees short of the fully open position. It can still be opened all the way by hand, and the phone has not been removed from the test rig.

How the machine works

CNET uses a device called the Fold-a-Phone, which opens and closes the handset automatically. A wire pulls the screen open, and earlier in the test it would pull back before the screen was fully open, letting the display coast the rest of the way.

Between 12:30 and 1 a.m. one morning, at around 440,300 folds, that changed. The screen no longer had time to open completely before the machine closed it again, which is how the wear became visible.

The phone is still working

Despite the hinge changes, CNET reports that the iPhone Duo remains operational. It is holding its other screen positions, and there are no signs of cracking or any other failure so far.

The test will continue until the phone meets one of several predetermined failure conditions. These include loss of power, sensors failing to detect the screen properly, or the screen going black.

The livestream runs on weekdays from 10 a.m. to 2 p.m. Pacific time, and CNET plans to keep folding until the device gives out.

How this compares with Samsung's displays

The iPhone Duo uses OLED panels sourced from Samsung Display, according to MacRumors. Samsung's screens have been through certified third-party fold testing, and the display in the Galaxy Z Fold7 passed a 500,000-fold durability test.

Apple is probably not using an off-the-shelf Samsung display, but CNET's results so far suggest the iPhone Duo's panel is on track to match that benchmark. Apple has not published results from its own internal hinge testing, nor has it given an estimated fold lifespan for the device.

What it means for buyers

The overall lifespan of a foldable phone depends on both the display and the strength of the hinge design. At around 450,000 folds, the iPhone Duo would last more than a decade for someone who folds it 100 times a day.

That figure suggests most owners are unlikely to reach the wear point CNET has observed through normal use. The final result will depend on when the phone hits one of the failure conditions, and the livestream is set to reveal that in due course.