The decision hinges on where the problem lives: cosmetic issues point to a redesign, structural or scaling problems call for a rebuild, and platform limitations that restrict content management or integrations signal a replatform. Evaluating the site across infrastructure, features, code, integrations, and front-end experience reveals which layer is actually holding performance back.
A useful diagnostic splits the site into front-of-house (what visitors see) and back-of-house (what the team operates). If the front-of-house is outdated, unresponsive, or has convoluted content but the CMS and integrations work fine, a redesign addresses the gap without a major technical overhaul. If the front-of-house is decent but the team struggles with content updates, workarounds, or integration gaps, a replatform targets the operational bottleneck. When both layers are broken, or when the project requires new taxonomy, restructured navigation, and rearchitected user journeys, the scope crosses into rebuild territory. The key questions to ask: Are we unhappy with how the site looks, how it works, or both? What is preventing the team from publishing content or shipping new features? Does the current setup align with where the business is heading in the next two to three years?