Building with Next.js and TypeScript at scale means making a few structural choices early. I prefer colocating routes with their data needs and using getStaticProps and getStaticPaths for content-heavy pages so we get fast loads and good SEO without extra client JS.
I keep shared UI in a components folder and use a small set of design tokens (colors, spacing) so the UI stays consistent. For state, I reach for React context or small stores only where needed; many screens can stay server-rendered and stateless.
Testing is easier when components stay presentational and data fetching lives in getStaticProps or API routes. I run E2E on critical flows and use type checking as the first line of defense. These habits keep the codebase predictable and easy to onboard to.