Most static servers enable If-Modified-Since header, as well as other detections... Cache sizes, specifically on mobile are very small, and ineffective... it&#x27;s more often than not, a very small http request to recheck if a cached file is still valid.<p>Optimizing images is a pretty huge thing, as is enabling gz compression on the streams... these two alone add up to far more saving than setting cache headers, not that they can&#x27;t or shouldn&#x27;t be set.