What is consistency in UI?

Consistency in UI is a principle according to which interface elements and interactions should be uniform across all parts of an application or product. This helps users navigate more quickly, reduces cognitive load, and enhances usability.

For example, if the "Back" button is always located in the same place and looks the same, users will not spend time searching for it or understanding its function in different screens. Consistency relates to colors, fonts, icons, element behavior, and terminology.