title: why would anyone set (Apache mod_expires parameter) ExpiresByType to "access plus 0 seconds"?
body: <p>In reviewing the answer to <a href="https://stackoverflow.com/questions/9933012/how-to-use-mod-headers-and-mod-expires-to-cache">this post</a>, I don't understand why 0 seconds is used for best practice here:</p>
  
  <pre><code>ExpiresByType text/html "access plus 0 seconds"
  </code></pre>
  
  <p>I <em>think</em> this means that whenever a user visits the website, the html page is always downloaded instead of pulled from cache. Is that right?</p>
  
  <p>Is this what people typically set for this variable? If so why? If not, which scenarios benefit from setting it to 0 seconds?</p>