A device's screen size, or display size, corresponds to the display's diagonal length. Typically listed in inches, the screen size has become one of the key factors when choosing electronics such as smartphones, tablets, monitors or TVs, and size seems to increase steadily for some of those categories.
Smartphones are a prime example of the continual growth of display sizes: just a few years ago, phones with screens bigger than 5.1 inches were seen as something between phones and tablets – hence the nickname "phablets." Nowadays, 5.1 inches is a phone's average screen size, taking into account old and new models. Smartphones whose screen sizes seemed entirely fitting just a while back may now look like miniature devices to you, and models as large as the Huawei Mate X (equipped with an 8-inch display) and the Samsung Galaxy Fold (with a 7.3-inch display) are now the first choices for people with different needs: from those who need bigger icons for accessibility issues to gamers and video streaming enthusiasts.
Whichever the type of product, a larger display doesn't necessarily mean a better one. Firstly, other aspects must be taken into account when choosing an electronic device based on its screen: the resolution, for instance, can make or break a product. Besides, there are individual needs and preferences, as not everyone wants to carry a "phablet" around and may find it challenging to handle a larger phone.
Finally, when it comes to TVs and monitors, there is such a thing as the ideal display size. The optimal distance between a full HD monitor or TV and the viewer is of four times the height of the screen, so having a 100-inch TV just two meters away from your couch wouldn't allow you to make the most of the viewing area. A product's aspect ratio is also relevant: TVs and smartphones with a 21:9 ultra-widescreen aspect ratio may be the smartest choice for those who would like to match the size of anamorphic movies.