This week in caching: browser cache headers worth re-reading

This week in caching: browser cache headers worth re-reading
Four signposts on Cache-Control directives most people misuse.
— immutable kills revalidation — Cache-Control: max-age=31536000, immutable on fingerprinted assets stops the browser from sending conditional requests on reload. Real bandwidth saved.
— no-cache != no-store — no-cache means "revalidate first," no-store means "never write to disk." People type the wrong one constantly.
— must-revalidate for stale-sensitive pages — forces re-check once expired instead of silently serving stale.
— the 7-day heuristic — without explicit headers, browsers guess freshness from Last-Modified; explicit max-age removes the lottery.
Bookmark: Jake Archibald's "Caching best practices" — the pattern of versioned-URL + immutable + index.html no-cache is the whole game.