Repetition Principle
Repetition is what keeps your design consistent and coherent — by reusing the same elements instead of reinventing the wheel every time.
This principle isn’t exclusive to design. It shows up in code, architecture, even furniture. If you buy 30 office chairs, you don’t pick 30 different ones (unless you're designing chaos on purpose).
In development, repetition isn’t just about copy-pasting — it’s about reuse. You write one component and reuse it across the interface. You don’t build 10 versions of the same dropdown from scratch — unless you enjoy pain.
Same in design.
Here's an infamous website that violated every rule imaginable. No repetition, no consistency — pure madness. (This is the old version; they eventually calmed down.)
Now compare that to a segment from Tailwind's landing page. Same colors, same layout, same structure — repeated with discipline. This is what systems look like.
Repetition isn’t laziness. It’s design clarity. When styles and patterns repeat, users start to trust the system. They know what a button looks like. They know what to expect. That’s good design.