title: viewWillAppear / viewDidAppear firing multiple times
body: <p>I am using <a href="http://cocoacontrols.com/platforms/ios/controls/tabbarkit" rel="nofollow">TabBarKit</a>, and I want to execute a request to pull a new peice of content from a webservice each time a user goes back to a tab.</p>
  
  <p>I can't put the request code in viewDidLoad as its not fired when coming back to the tab. With that said, I've noticed viewWillAppear / viewDidAppear are called multiple times when returning back to a tabs view controller.</p>
  
  <p>If I put the requesting code in there, it is fired multiple times resulting in the webservice being pinged needlessly. </p>
  
  <p>How can I solve this problem? Which method should I place my HTTP request call in so it executes once per view?</p>