Well SaidThe Plaid Cow on 05 Sep 2008
Wordpress Login Cookie
Regarding the Wordpress login cookies, I agree with Mike. If I don’t log in for a while, then feel free to sign me out. Just don’t make me log in what seems like every other day.
To fix it in version 2.6.1, search wp-includes\pluggable.php for
$expiration = $expire = time() + 1209600;
and adjust the number of seconds the cookie should live for.