Fresh vs. Familiar: How Aggressively to Redesign

Jakob Nielsen reasoning why it’s best to make gentle changes, rather than go with spaghetti on the wall:

Generally, it’s best to evolve a UI with gentle changes rather than offer a totally fresh design. I thus strongly recommend getting the basic design right in the first place, before you launch, so that it can live for several years with minor updates. Before you release anything to customers, use techniques such as rapid iterative design and paper prototypes to thoroughly explore the design space and polish the usability.

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