title: Firebase: should I store user data on the authentication profile or database
body: <p>I signed up a user in my Flutter app using <code>FirebaseAuth.instance.verifyPhoneNumber()</code>. This works perfectly and the user shows up in my Firebase Console.</p>
  
  <p><code>FirebaseAuth.instance.currentUser()</code> now returns the user for me whenever I open the app. <strong>Should I store user info (age, weight etc.) here, or should I create a <code>users</code> collection in my <code>Database</code> and link the <code>currentUser().uid</code> in there?</strong></p>
  
  <p>Also, should I store it on the Database linked against the <code>uid</code>, or linked against the login info. For example, link a <code>user</code> to the <code>phoneNumber</code> and not the <code>uid</code>. Because if you ever delete the user, but they want to register again, then they will get a new <code>uid</code>, but their <code>phoneNumber / email</code> will still stay the same and can therefore still link to their old data.</p>