Next.js Fetch Caching Serving Stale Data

1. Using default fetch cache without explicit revalidate time
2. Revalidate time set too high, keeping stale data too long
3. Not using revalidateTag() for on-demand revalidation
4. Browser cache conflicting with Next.js cache (Set-Cookie, Cache-Control headers)
5. ISR not triggering revalidation properly on deployment

Set revalidation: Control cache duration:
fetch(url, { next: { revalidate: 3600 } }) caches 1 hour. Use 0 for no cache.

Use revalidateTag(): For on-demand updates:
fetch(url, { next: { tags: ['posts'] } })
// In server action: revalidateTag('posts')

Disable cache for dynamic data: const data = await fetch(url, { cache: 'no-store' }) always fetches fresh.

Check headers: Ensure Cache-Control header set correctly. Vercel sets cache headers automatically, don't override.