Consistency means the same concept looks and behaves the same everywhere — vocabulary, components, spacing tokens, motion — shrinking learning curve and support load.
Internal and external
Match your design system AND platform expectations. Deviations need documentation and stronger affordances.
Copy consistency
“Delete” vs “Remove” vs “Trash” for the same action confuses. Maintain a product glossary.
Behavioral consistency
Same interaction yields the same result: keyboard shortcuts, hover vs tap parity, and predictable validation timing.
Practices
- Design tokens for color, space, radius.
- Lint UI for one-off hex codes.
- Shared component library with usage notes.
Common pitfalls
- One-off button styles per screen.
- Renaming nav items between sections.
- Dark-mode palette unrelated to light-mode roles.