I agree with ACORN. But I came across a problem on web hosting where they have their CACHE. So the only solution is HTACCESS - where they have to set up CACHE deletion or ask the web host to turn it off, which they don't recommend.

<IfModule mod_expires.c>
ExpiresActive On
ExpiresDefault A600
ExpiresByType text/javascript A604800
ExpiresByType application/javascript A604800
ExpiresByType text/css A604800
ExpiresByType image/gif A604800
ExpiresByType image/png A604800
ExpiresByType image/jpeg A604800
ExpiresByType image/x-icon A604800
ExpiresByType text/html A60
</IfModule>