Prize consistency over novelty

Why this rule exists

A user learns a product once and then relies on that learning everywhere within it, so every place your interface behaves the same way, it teaches a lesson that pays off across the whole product, and every place it behaves differently, it charges a small tax of surprise. The temptation to make each screen fresh and special works directly against this, because novelty within a product fragments the user's understanding and forces them to re-learn what they thought they knew. Consistency, in layout, in language, in behavior, in the meaning of colors and controls, is what lets a product feel like one coherent thing rather than a collection of screens made by different hands. It is also invisible when done well, which is why it is so often undervalued, but its absence is felt immediately as an interface that seems arbitrary and untrustworthy. A predictable product is a learnable product, and predictability comes from doing the same thing the same way every time, even when a fresh variation would have been more fun to make.