A short list that catches most of what reviewers would catch.
The short version
Caching hides problems as often as it solves them. A page that is fast only when the cache is warm is a page that falls over on the morning after a release, which is exactly when people are looking at it. Test the cold path on purpose. Clear everything, load the home page once, and read what the database had to do.
Nothing here needed a new plugin. The fix was a small change to a query and a better idea of when to run it. That is usually the case: the expensive part of a site is rarely the code you can see, and adding a layer on top only moves the cost somewhere harder to find. Delete first, then decide what is still missing.
If you cannot explain why it is fast, it is only fast today.
Priya Raman
What we found first
Escaping belongs at the point of output, where a reviewer can see it. When a value has been cleaned three functions earlier, nobody can tell by reading the template whether it is safe, and the next person to touch that line will not know either. We moved every escape next to its echo and the file got shorter and easier to trust.
The review took longer than the fix, and that is the right way round. Most of the time went on working out what the code was meant to do and who depended on it. Once that was written down, the change itself was four lines, a test and a note in the changelog that future maintainers will actually thank us for.
Why it matters
A throwaway site is the cheapest tool in the kit. We can build one in a minute, break it completely and delete it without a single awkward conversation. Everything risky in this post happened there first, including the mistakes we are not going to mention, and nothing touched production until it had survived a full run from a clean start.