A phone is more useful when you can comfortably read its messages and menus. This earns a place because it improves an existing device without replacing the screen. It opens our countdown as a broadly available adjustment, though for someone who needs larger text it may matter more than every feature above it.

On iPhone, look under Display & Brightness for Text Size, or Accessibility for larger text options. On Android, search Settings for Font size and Display size. Check your usual apps after moving the sliders: some do not follow the system font setting, and very large text can make controls awkward to reach.

Official guides: Apple · Google.

Illustration: Topnilo; phone icon by Assaf Katz, adapted. All artwork: CC0.