title: Accessing NSUserDefaults Often
body: <p>During a logic process in my app, I need to access the user preferences frequently, and a bunch of times 10~15 to determine what needs to be processed and how. May this question is not about performance, but about doing it correctly.</p>
  
  <p>Currently I'm doing a <code>[[NSUserDefaults standardUserDefaults] valueForKey:...]</code> each time I need to request a value. Is this correct? I think that "saving" the user defaults as an ivar could reduce extra work, but then I wonder if this won't have sync problems, like if the user changes the preferences and they get updated only if the app is restarted (so the user defaults object is recreated).</p>
  
  <p>Is there any better way?</p>