This is what I use to control headers/caching, I'm not an Apache pro, so let me know if there is room for improvement, but I know that this has been working well on all of my sites for some time now.
http://httpd.apache.org/docs/2.2/mod/mod_expires.html
This module controls the setting of the Expires HTTP header and the max-age directive of the Cache-Control HTTP header in server responses. The expiration date can set to be relative to either the time the source file was last modified, or to the time of the client access.
These HTTP headers are an instruction to the client about the document's validity and persistence. If cached, the document may be fetched from the cache rather than from the source until this time has passed. After that, the cache copy is considered "expired" and invalid, and a new copy must be obtained from the source.
# BEGIN Expires
<ifModule mod_expires.c>
ExpiresActive On
ExpiresDefault "access plus 1 seconds"
ExpiresByType text/html "access plus 1 seconds"
ExpiresByType image/gif "access plus 2592000 seconds"
ExpiresByType image/jpeg "access plus 2592000 seconds"
ExpiresByType image/png "access plus 2592000 seconds"
ExpiresByType text/css "access plus 604800 seconds"
ExpiresByType text/javascript "access plus 604800 seconds"
ExpiresByType application/x-javascript "access plus 604800 seconds"
</ifModule>
# END Expires
http://httpd.apache.org/docs/2.2/mod/mod_headers.html
This module provides directives to control and modify HTTP request and response headers. Headers can be merged, replaced or removed.
# BEGIN Caching
<ifModule mod_headers.c>
<filesMatch "\.(ico|pdf|flv|jpg|jpeg|png|gif|swf|woff|woff2|ico)$">
Header set Cache-Control "max-age=2592000, public"
</filesMatch>
<filesMatch "\.(css)$">
Header set Cache-Control "max-age=604800, public"
</filesMatch>
<filesMatch "\.(js)$">
Header set Cache-Control "max-age=604800, private"
</filesMatch>
<filesMatch "\.(xml|txt)$">
Header set Cache-Control "max-age=216000, public, must-revalidate"
</filesMatch>
<filesMatch "\.(html|htm|php)$">
Header set Cache-Control "max-age=1, private, must-revalidate"
</filesMatch>
</ifModule>
# END Caching
To enable:
a2enmod headers && a2enmod expires && service apache2 restart
To disable:
a2dismod headers && a2dismod expires && service apache2 restart