title: Correct way to display current date/time in iOS app and keep it up to date
body: <p>I'm wondering this primarily out of the theory/performance side of things, but if I needed to display the current date/time in a UILabel or something, and then keep it up to date (say, down to the minute), what is the most correct way to do so?</p>
  
  <p>I've seen various examples online of "clock" apps that basically just have a recursive method that runs with a 1 second delay between invocations.  Another option would be to create a repeatable timer and add it to the run loop.  There are probably a variety of other ways to do this as well.  Is there one way that is better than the others?</p>