I have medium control over a webserver (host service), and I have a directory for which I don't want anything to be cached.
(I didn't have the opportunity to set it, and since then people did view it, so I need to address old users too.)
This gives quite a comprehensive response:
How do we control web page caching, across all browsers?
but I have two issues with it: (a) it doesn't cover PDFs or other binaries; (b) for HTML, it would be too late for some users, if I can't get them to refresh first.
Can I use something like .htaccess or otherwise to ensure this directory and its files are always refreshed?
(Apache server, I believe)