Google’s Page Speed test recommends the we leverage browser caching. To do this in Windows using IIS, open the site’s web.config and add a client caching directive:
<system.webServer>
<staticContent>
<clientCache cacheControlMode=”UseMaxAge” cacheControlMaxAge=”365.00:00:00″/>
</staticContent>
</system.webServer>
**There are “per file” rules that can be applied but this seems to be sufficient for Google