UI performance
Keep imports, styles, responsive rules, and server-rendered component trees predictable without relying on unsupported size claims.
Keep application cost understandable
Use focused imports when ownership and review clarity matter; use grouped or root imports when they make a feature easier to maintain.
Do not load both plugin-managed theme CSS and a separately generated theme file.
Prefer component props for repeated responsive behavior and reserve sx for genuinely local exceptions.
Reuse stable sx objects where practical instead of generating a different rule on every render.
Keep large overlays, tables, charts, and route-only compositions out of application shells that render on every page.
Understand style deduplication and benchmarks
The client style cache indexes hydrated style records once and then resolves them by id. Server benchmarks include both component markup and style collection, so a realistic regression review considers render time and output size together.
The repository benchmark records mean, median, p95, min, max, operations per second, HTML bytes, style count, style bytes, and heap delta.
Missing component fixtures and render errors fail the benchmark.
Timing and size regressions are currently reported as warnings rather than enforced thresholds.
Repository benchmark methodology is useful for maintainers; applications should measure their own routes and interactions.