Buying a Used Foldable Phone: How to Check the Hinge, Inner Display and Locks
· TR Vertriebs GmbH
With the iPhone Duo, Apple is entering the foldable market, and Samsung's eighth Fold generation has been on sale since August. Foldables are growing in 2026 while the overall smartphone market shrinks – and the current Samsung and Apple models start at 1,299 to 2,299 euros. What buyers of used foldables need to check on top of the usual.
On 9 September, Apple unveiled its first foldable iPhone. The iPhone Duo has a 7.6-inch inner display and a 5.4-inch outer display, costs from 2,299 euros in Germany and goes on sale on 23 October, with pre-orders opening on 16 October. Samsung has been selling its eighth generation since 7 August: according to the manufacturer, the Galaxy Z Fold8 starts at 1,999 euros, the Fold8 Ultra at 2,199 euros and the Galaxy Z Flip8 clamshell at 1,299 euros. Anyone who wants a foldable for less ends up in the used market – and has to check things there that do not matter on a conventional smartphone.
The supply of used devices is likely to grow, because this segment is expanding against the trend. In its forecast of 26 August, market researcher IDC expects global smartphone shipments to fall by 16.7 percent in 2026, while foldable shipments rise by 12.6 percent to 22.9 million units. According to a report from 8 September, Counterpoint Research expects more than 100 million foldable smartphones to have shipped in total by the end of 2026, and forecasts up to six million foldable iPhones shipped by Apple this year.
The most sensitive component is the inner display. Unlike on a conventional smartphone, its surface has to stay flexible: for the iPhone Duo, Apple describes a scratch-resistant coating and a nano-texture top layer made of a special polymer, with high-strength glass beneath; Samsung applies a protective film to the main display at the factory. Inspect the opened display under light falling at an angle. Some crease in the middle is inherent to the design, but bubbles, lifting film edges, pressure marks, scratches and pixel defects along the fold line are warning signs. Show a white and then a black image and swipe your finger across the entire surface, especially over the middle, to find dead spots in touch detection.
On Samsung devices, it pays to ask about that film. Samsung advises against removing the pre-installed protective film on the main display. Removing it does not void the warranty, but any damage to the display caused in the process has to be paid for by the customer. In Germany, Samsung replaces the film free of charge up to four times during the first 24 months, at most twice per year – provided the display and frame are otherwise undamaged. If the film is missing or damaged, ask why and ask for service records. If the purchase was less than 24 months ago, check the invoice: a free film replacement may still be possible.
The second wear part is the hinge – on the iPhone Duo, according to Apple, it consists of more than 100 individual parts. Open and close the device fully several times. It should move evenly, without grinding or rubbing, hold intermediate positions and close completely; grinding suggests foreign particles in the mechanism. Pay attention to the protection rating as well: Samsung specifies IP48 for the Fold8, Fold8 Ultra and Flip8. According to Samsung, the 8 stands for protection when submerged up to 1.5 metres for 30 minutes, in fresh water only. Under the IEC 60529 standard, the 4 only means protection against solid objects of one millimetre or larger – that is not dust-tight.
According to Apple, the iPhone Duo is rated IP68, which also covers dust, and is protected up to a depth of six metres for up to 30 minutes. Apple points out, however, that water and dust resistance is not permanent and may decrease as a result of normal wear, and that the warranty does not cover liquid damage. For used buyers this means the rating describes the device when new. How well a used device still seals after drops or years of use cannot be checked at the point of sale.
Repair costs show why these checks matter. For the inner display of the Galaxy Z Fold7, Notebookcheck reported a parts price of 761 euros in July 2025, citing a European spare parts supplier, and 525 euros for the cover display – in each case excluding labour. For the Galaxy Z Flip7, the figures were 342 and 207 euros respectively. Anyone who buys a used foldable without remaining warranty or insurance carries that risk alone. So ask to see the original invoice and find out whether the manufacturer's warranty is still running and whether repairs are documented.
The lock check for foldables is the same as for any smartphone, but because of the high prices it matters even more. Ask for the IMEI in advance and check the blacklist and lock status. Since these devices usually support two SIM profiles, *#06# typically shows two IMEIs; both should match the settings and the box. On Samsung devices, the seller must remove their Google account before resetting, otherwise Factory Reset Protection keeps the device tied to their account; the Samsung account should be signed out too. On an iPhone, Find My must be turned off and the device removed from the seller's Apple Account, otherwise Activation Lock applies.
The iPhone Duo adds two special points. According to Apple, it works with eSIM only, worldwide; there is no SIM tray for testing with your own card, so the network lock status has to be checked via the IMEI. And instead of Face ID, Touch ID is built into the side button – after a reset, test whether you can enrol your own fingerprint. Above all: nobody can own an iPhone Duo from a retailer before 23 October. If someone offers one as “used” or “sealed” for payment in advance before then, it is very likely a scam.
All in all, a used foldable can be a good deal precisely because new prices are so high. But checking one takes longer than a conventional smartphone: the inner display and film, the hinge, the paperwork – and above all the lock status. With IMEI Safe, you can check the IMEI for blacklist entries and locks before you meet, so you know whether the trip is worth it at all.