Nine mistakes your foldable phone will never forgive you for

Take care not to damage the crease and only apply very light pressure to the most sensitive area of the inner display. Franziska Gabbert/dpaA fairly small, conventional screen on the outside, but tablet-worthy dimensions when unfolded: foldable and flip smartphones, also known as foldables, offer the best of both worlds. They are easy to carry and can be propped up in different ways thanks to their hinges.

However, the highly complex inner screens and hinges are the Achilles' heel of foldables, even though manufacturers have made these parts much more robust in recent years.

Before folding or unfolding a phone, you need to check that its hinges are clear and that nothing is on the screen. Never force it open or closed if there is resistance, and never treat the inner screen like ordinary glass.

The most widely available folding smartphone brands are Samsung, Motorola, Honor, Huawei and Oppo, while Apple is set to launch its iPhone Duo later in October.

What manufacturers warn about when using their current foldable and flip smartphones:

1. Never peel off the inner-screen protective film

Manufacturers generally protect the inner screens of their foldables with a pre-installed specialist film. This must never be peeled off or replaced by the user. Replacing it is a job for customer service because the film is an integral part of the display unit. If scratches, cracks, bubbles, cloudiness or other damage are a problem, or if the film simply comes loose, it is time to contact customer service about a replacement.

Folding phones are particularly sensitive to hard impacts, which can damage the screen. Coloured dots or lines, black spots or cracks indicate damage, especially if they spread to surrounding areas or a white line appears when the phone is folded.

If the inner screen is set up for stylus input, that still does not mean you can use any stylus. To avoid damage, follow the manufacturer's recommendation.

As far as possible, avoid pressing on the inner screen along its crease. In general, use as little force as possible whenever you touch the screen, whether using a stylus or cleaning it.

When folding the phone, make sure there are no objects or foreign bodies, such as bank cards, keys or sand, between the two screen halves. This helps prevent damage. After all, a foldable is not a suitcase, and there is virtually no space between the screens when folded.

6. Try to avoid things being dropped on the inner screen

Pens, scissors, glasses or other objects can slip out of your hand or get knocked over and damage the screen. Make sure none of them lands on the inner screen.

You only have one hand free, but need to open the foldable? Don't push a finger between the screen halves to lever it open. Always open the device properly with both hands in one smooth movement.

Most foldables are designed to resist dust and water, although the degree of protection varies. Check the stated IP rating and the specific guidance for your model. In general, try to avoid contact with small particles such as dust and sand to prevent screen damage and avoid unnecessarily shortening the hinge's lifespan.

9. Clean gently, without using a fingernail

Clean the inner screen with a soft, lint-free microfibre cloth. Always work gently and without pressure. Resist the temptation to use your fingernail, for example. Never use rough-surfaced cloths that could scour the screen, such as paper tissues or kitchen roll. Cleaning liquids should also generally be avoided. Check the guidance for your model to see whether the manufacturer recommends any and, if so, which. Household cleaning products are always off limits, including glass cleaner.

Foldables like the iPhone Duo (pictured) need gentler hands than your average smartphone. Andrej Sokolow/dpa