Joanna Stern’s machine-fold test shows the iPhone Duo hinge remains stiff and feels unchanged after thousands of cycles.
Key points
- Joanna Stern used a custom machine to fold an iPhone Duo more than 32,000 times over four nights.
- Instrumented measurements showed the hinge became stiffer, though manual handling felt identical to day one.
- Apple has not released official durability data, while Samsung cites 500,000-fold tests for its 2025 devices.
A reviewer subjected an iPhone Duo to thousands of mechanical folds to assess its physical durability. The test found no perceptible degradation in the hinge mechanism after the extensive stress cycle.
What happened
According to MacRumors, Joanna Stern used a custom-built device to fold an iPhone Duo review unit more than 32,000 times over a four-night period. She noted that while she initially suspected the hinge might feel looser as the cycle count increased, her final assessment was that she could not detect significant change. A calibrated push-pull gauge recorded readings before and after the test, indicating the hinge was actually stiffer than at the start. Despite the instrumented data showing increased stiffness, Stern stated that in everyday handling, the device felt nearly identical to its condition on day one.
The testing was conducted with a case on the device. The machine opened the phone flat but did not close it completely during each cycle. Stern did not report whether the screen crease became more visible, a common issue with other foldable phones over time. Apple has not shared official hinge test results or a lifetime fold count for the iPhone Duo. In contrast, Samsung Display stated in 2025 that the Galaxy Z Fold7 display passed a 500,000-fold durability test. Samsung claims this rating supports over ten years of use for users folding the device about 100 times daily.
Why it matters
Foldable devices rely on complex mechanical hinges that endure repeated stress. Manufacturers often cite laboratory durability numbers that assume ideal conditions and moderate usage. Independent tests help verify whether these mechanisms hold up under real-world handling. Users should understand that official ratings may not reflect heavy daily use or accidental impacts. Physical wear can affect hinge tension and screen alignment over time. Checking for consistent resistance and visual creasing helps identify early degradation. Understanding the difference between machine-tested limits and actual user experience is key for long-term ownership decisions.
The fix
- Monitor the hinge for changes in resistance or looseness during daily use.
- Inspect the screen crease area for increased visibility or discoloration.
- Avoid forcing the device open or closed beyond its natural range of motion.
- Keep the device in a protective case to shield the hinge mechanism from debris.
Why it matters
When evaluating foldable technology, users must distinguish between controlled lab results and practical longevity. Teams usually recommend tracking hinge stiffness and screen integrity as primary indicators of health. Check whether the device maintains consistent closing pressure over weeks of use. Look for any new gaps or misalignments around the folding axis. These physical signs often precede functional failures. Regular visual inspection of the display crease can reveal early material fatigue. Understanding these mechanical limits helps manage expectations for device lifespan and performance.
What to do and how to stay safe: iPhone Duo
- Observe the hinge mechanism for any new looseness or resistance changes during normal operation.
- Examine the screen crease daily to detect any widening or increased visibility over time.
- Avoid applying excessive force when opening or closing the device to prevent mechanical strain.
- Use a protective case to minimize exposure of the hinge area to dust and physical impacts.
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General security guidance from the Crypt Weekly newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
How many times was the iPhone Duo folded in the test?
Joanna Stern’s custom device folded the iPhone Duo more than 32,000 times over four nights.
Did the hinge feel different after the test?
Stern concluded she could not feel much of a difference in everyday use after the 32,000 folds.
Does Apple provide official fold durability numbers?
Apple has not shared iPhone Duo hinge tests or given a lifetime fold number like Samsung.
