title: How many NSOperationQueues is too many?
body: <p>Is it a good practice to have multiple <code>NSOperationQueue</code>s?  I currently am writing an application that has a <code>NSOperationQueue</code> that kicks off multiple <code>NSOperation</code>s.  Each operation then starts its own queue and executes its own separate <code>NSOperation</code>s.  I don't have any issues with this model so far and everything is operating as it is supposed to (I'm not experiencing any deadlock).</p>
  
  <p>Is that considered a good practice?  Is there a point where you have too many <code>NSOperationQueue</code>s?</p>