The fit of the headphones.
We consider a lower weight better because lighter devices are more comfortable to carry. A lower weight is also an advantage for home appliances, as it makes transportation easier, and for many other types of products.
With a detachable cable you can use alternative cables, and if the cable is pulled it will pop out instead of breaking.
The first number of the IP rating refers to protection against dust, while the second number refers to protection against liquid. E.g. a first number of 6 denotes that it is completely dustproof, and a second number of 7 denotes that the device can withstand full immersion in water.
Foldable devices are easier to transport and take up less storage space.
The cable is designed to minimize tangling.
The device comes with its own special case or pouch, which is useful for safe transportation.
The device is designed in a way that allows sound to go out through the back of the ear cups, which usually have vents or perforations. This design provides very natural and accurate sound.
The device is dustproof and water-resistant. Water-resistant devices can resist the penetration of water, such as powerful water jets, but not being submerged into water.