Gatsby's Incremental Builds feature significantly reduces build times for static sites by allowing only the changed content to be rebuilt, rather than the entire site, which is especially beneficial for large sites with extensive pages. This is made possible by Gatsby's unique Data Layer, powered by GraphQL, which separates content updates from the complete build process. Incremental Builds function in both published and preview states on platforms like Gatsby Cloud, enabling marketers and content creators to see updates almost in real-time without lengthy delays. To utilize this feature, users need to sign up for a Gatsby Cloud account and connect to a compatible headless CMS, such as Contentful or WordPress, with seamless integration for efficient content management and site deployment.