Users do not measure milliseconds — they feel responsiveness. Optimizing perceived performance is often higher leverage than raw speed.
Render less, later
Virtualize long lists, defer off-screen work, and split heavy screens. The fastest render is the one you never do. On dense CRM dashboards, windowing alone transformed scroll smoothness.
Optimistic UI
When an action is very likely to succeed, update the UI immediately and reconcile in the background. The app feels instant, and the rare failure is handled gracefully. A well-designed API and cache layer is the single biggest lever here.
Cache like you mean it
RTK Query with sensible invalidation means most navigations are instant because the data is already there. Treat the cache as a first-class part of the architecture, not an afterthought.
Measure what users feel
Time-to-interactive and input latency matter more than synthetic benchmarks. Watch the metrics that map to how the app feels in the hand.