title: iPhone View Controller Register
body: <p>Hi i'm pretty new to iPhone development, looking to put together a fairly substantial app and just wondering should View Controllers which are used later in the lifecycle of the app be registered in the AppDelegate at the start of just introduced as needed? </p>
  
  <p>For example I start with a login page which requires a UINavigationController so I register with AppDelegate and i'm away, however following an intermediary page I'm 
  using a TabController so do I just introduce it on the 3rd page or register in AppDelegate?</p>
  
  <p>More of an architectural best practice issue really :)</p>