Incremental Static Regeneration (ISR) enables you to:
Update static content without rebuilding the entire site
Reduce server load by serving prerendered, static pages for most requests
Ensure proper cache-control headers are automatically added to pages
Handle large amounts of content pages without long next build times
During next build, all known blog posts are generated (there are 25 in this example)
All requests made to these pages (e.g. /blog/1) are cached and instantaneous
After 60 seconds has passed, the next request will still show the cached (stale) page
The cache is invalidated and a new version of the page begins generating in the background
Once generated successfully, Next.js will display and cache the updated page
If /blog/26 is requested, Next.js will generate and cache this page on-demand