title: Facebook OAuthException: This authorization code has been used
body: <p>This question is related to this <a href="https://stackoverflow.com/questions/13752959/oauthexception-this-authorization-code-has-been-used-facebook">question</a> already asked.</p>
  
  <p>Does this Facebook change mean that we have to store the user token returned the first time and reuse that for all subsequent Facebook requests?  What happens if we do not store this user token - can we request it again?  If yes, how do we do that?</p>
  
  <p>Also, when does the user token expire, if it ever expires?</p>