If you remove the
ETag header, you will totally eliminate
If-None-Match requests and their
304 Not Modified Responses, so a file will stay cached without checking for updates until the Expires header indicates new content is available!
Please don't turn off ETags and Last-Modified headers for your .html files, leave one of them ON. (I use Last-Modified for .html).
This goes in your root .htaccess file but if you have access to
httpd.conf that is better.
<FilesMatch "\.(ico|pdf|flv|jpg|jpeg|png|gif|js|css)$"> Header unset Last-Modified </FilesMatch>
Cache-Control header and
Expires header, you can specify that certain files be cached for a certain period of time, and you magically (this is a really unique trick I promise) eliminate any validation requests!!