The App Router rewards a clear hierarchy: layouts for shared chrome, loading.tsx for instant feedback, and error boundaries that fail gracefully instead of blank screens.

I keep data fetching close to where it’s used — server components by default, client boundaries only where interactivity demands it — so bundles stay honest and mental models stay simple.

As routes multiply, co-locating feature code and naming routes after user journeys (not implementation details) helps onboarding and keeps refactors localized.