title: Should switch statements always contain a default clause?
body: <p>In one of my first code reviews (a while back), I was told that it's good practice to include a default clause in all switch statements.  I recently remembered this advice but can't remember what the justification was.  It sounds fairly odd to me now.</p>
  
  <ol>
  <li><p>Is there a sensible reason for always including a default statement?</p></li>
  <li><p>Is this language dependent?  I don't remember what language I was using at the time - maybe this applies to some languages and not to others?</p></li>
  </ol>