What Actually Clears W3 Total Cache's Page Cache (It's More Than You Think)
A 30-day cache lifetime, and still the page cache kept shrinking overnight. Tracing every code path that purges W3 Total Cache turned up a purge policy that applies to far more than posts, a menu save that wipes the whole cache, a double-flush pattern common to plugins that save posts, and the reason priming a page right after purging it does nothing at all.