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Caching is the temporary storage of frequently accessed data in higher speed media (typically SRAM or RAM) for more efficient retrieval. Web caching stores frequently used objects closer to the client through browser, proxy, or server caches. By storing "fresh" objects closer to your users, you avoid round trips to the origin server, reducing bandwidth consumption, server load, and most importantly, latency. This article shows how to configure your Apache server for more efficient caching to save bandwidth and improve performance. Caching is not just for static sites, even dynamic sites can benefit from caching. Graphics and multimedia typically don't change as frequently as (X)HTML files. Graphics that seldom change like logos, headers, and navigation can be given longer expiration times while resources that change more frequently like XHTML and XML files can be given shorter expiration times. By designing your site with caching in mind, you can target different classes of resources to give them different expiration times with only a few lines of code.