title: Does ConfigurationManager.AppSettings[Key] read from the web.config file each time?
body: <p>I'm wondering how the <code>ConfigurationManager.AppSettings[Key]</code> works.</p>
  <p>Does it read from the physical file each time I need a key? If so, should I be reading all the app settings of my web.config in a cache and then read from it?</p>
  <p>Or does ASP.NET or IIS load the web.config file only once at application startup?</p>
  <p>How do I verify whether the physical file is accessed by each read? If I change the web.config, IIS restarts my application, so I can't verify it that way.</p>