<i>&gt; They&#x27;re still unique to you.</i><p>Nope. Most free email providers out there (including gmail) have policies for username expiration, some even quite aggressively (like one month without login). &quot;Me&quot; on one of these services might not be &quot;me&quot; in three months&#x27; time, but you-website won&#x27;t know that and will happily send a password reset link to my old email.