Farm shops: the danger is a stale cache, not a slow one

Farm shops have a rhythm most retail does not: what is available changes weekly, sometimes daily, and the whole proposition is that the information is true. A customer who drives twenty minutes for something you sold on Saturday does not come back.

That collides with how caching works. The cache holds a built copy of a page so the server does not have to assemble it again, and it holds that copy until told otherwise. Most of the time this is exactly what you want. On your availability page it is the failure mode.

So this page is about purge rules, cache lifetimes and how to verify what a real visitor is being served — plus the collection-slot flow, which never caches at all.

Two tools solve it. Set a shorter cache lifetime on the availability page, or purge it explicitly whenever the list changes — a scheduled purge on a Monday morning costs nothing and removes the whole class of problem. Reserve outright exclusion for pages that genuinely must be built fresh every time, because an excluded page has no cache protection at all when traffic arrives.

Verify rather than trust. Open the page in a private window after every update. New list plus a cache hit means the rules are right. Old list means the purge missed that URL, and now you know exactly which rule to add.

Every rule above fails if updating the list is a chore. Keep it to one short page, edit it on a Monday, and let the purge happen on publish. If the list has moved into a plugin or a feed, add a scheduled purge so the cache refreshes whether or not anything was published.

Test the whole loop once on staging: change the list, purge, load in a private window, confirm the new content and the cache hit. Once you have watched it work you will trust it, and trusting it is what keeps the page accurate.