Methods and systems for cache optimization are described. Content items served to client devices of a content distribution network may be associated with a cache value. The cache value for a content item may cause a cache device to cache the content item for a period of time. The cache value for the content item may be updated based on increasing or decreasing popularity. The content item may be encoded at a plurality of bitrates, and cache values may vary across the plurality of bitrates such that multiple copies of the content item may each be cached for varying periods of time depending on a corresponding bitrate.