title: When I should load a new access token?
body: <p>My app uses Facebook Javascript SDK authorization on client side, and for authorized user app fetches access token from Facebook API, using facebook cookie with signed request and provided <code>code</code>, and store it into database. </p>
  
  <p>Everything is working fine, but i'm wondering, when I should refresh stored access token? What if user have changes password, and have signed in/connected again. </p>
  
  <p>As I understand, now she has new access token, and app should load it from Facebook. But how I can understand when I should check for a new token? Check on each request with facebook cookie doesn't work, because it's few request per second for each user (event if she didn't change a password). Or maybe i'm doing something wrong?</p>
  
  <p>I mean:</p>
  
  <ul>
  <li>I've authorized user on client side</li>
  <li>I've cookie with signed request</li>
  <li>Signed request is pretty enough to authorize user on server side (validate user credentials)</li>
  <li>I can get <code>access token</code> by calling Facebook API, anytime when user user makes request to my app (because I need a <code>code</code> from signed request). So, i'm doing it when I don't have stored <code>access token</code> or existing <code>access token</code> has expired.</li>
  <li><code>access token</code> just stored in database, and can be used anytime, in different thread, maybe few minutes later (mean we don't have user request and cookie with signed request)</li>
  <li>What if stored <code>access token</code> not expired, but invalidated on facebook side? I need to fetch new <code>access token</code>, but cookie has gone at this moment.</li>
  </ul>
  
  <p>Currently I see only one way: store <code>code</code> from signed request into databse, and when we have found that we have invalid <code>access token</code>, try to load it. But i'm note sure that it's proper way, and not so much usable for most cases</p>