title: How long will cached CSS file get updated in browser?
body: <p>How long will cached CSS file get updated in browser if I don't do anything specifically?</p>
  <p>I googled this but haven't found a clear answer. I know I can use <code>file.css?v=1</code> to force the browser to load the updated version or I can use hard reload feature of the browser. But what if I don't do all of these? So far the browser will always load the cached old version.</p>
  <p>Without hard reload and any other setup in server, how long will a local browser update the cached CSS file? Will the cached version stay there forever? <em>(unless the cache space is full to make space)</em>.</p>