Rendering strategy
Static generation for marketing, ISR for semi-dynamic, SSR only when you have to. Client-only renders are a ranking liability unless you're tiny.
Hydration costs
Big client bundles break Core Web Vitals. Split routes, lazy-load heavy components, and use React Server Components where possible.
Testing rendered output
Use Google's URL Inspection tool weekly on critical pages. Don't assume what's in your browser matches what the Googlebot crawler sees.