Preventative Design

Preventative Design focuses on anticipating and addressing potential user errors or frustrations before they occur. This approach aims to minimize the likelihood of mistakes, misunderstandings, or usability issues by designing intuitive interfaces, providing clear instructions, and offering proactive feedback, such as input validation or confirmation messages, to guide users through tasks smoothly.

Preventing errors is almost always cheaper than recovering from them — both for your users (who don't lose work or get confused) and for your team (fewer support tickets, less error handling code). Common preventative design techniques include disabling actions that would cause errors, providing format hints before submission, auto-correcting common mistakes, and writing constraints into UI components so invalid states are never reachable.

Calendar applications prevent double-booking by visually blocking occupied time slots — you can't select a time that's already taken, so the error (scheduling a conflict) is prevented at the UI level rather than handled after the fact with an error message.