//210delete_sentmail_monthly
// purge sent-mail folders every month?
$_prefs['delete_sentmail_monthly'] = array(
    'value' => 0,
    'locked' => false,
    'shared' => false,
    'type' => 'checkbox',
    'desc' => _("Delete old sent-mail folders at beginning of month?"),
    'help' => 'prefs-delete_sentmail_monthly');
