<b>The blog cached six times over for no reason</b>

<b>The blog cached six times over for no reason</b>

A travel blog had a respectable 70% cache-hit ratio but a strangely huge edge storage footprint. The culprit was a <code>Vary: User-Agent</code> header their CMS emitted by default. Every browser-version string created a separate cached copy — the same article stored hundreds of times across phones, tablets, and desktop variants.

The content didn't actually change by user-agent; it was responsive CSS doing all the work. We dropped <code>Vary: User-Agent</code> and varied only on <code>Accept-Encoding</code>, which genuinely matters.

The number of edge objects collapsed by roughly 200x. Cache-hit ratio jumped from 70% to 95% because new visitors now landed on an already-warm copy instead of a user-agent-specific cold one. Edge storage and origin fetches both dropped sharply.

The number that mattered: ~200 cached copies per article down to 1.