CheckUsefulDay.php

<?php

$wk = now()->dayOfWeekIso;
$da = now()->day;


if ($wk <= 4) {
    if ($wk == 1) {
        // toda segunda feira
        $type = 'weekly';
    } elseif (($da >= 15 || $da <= 18) && ($wk >= 1 || $wk <= 4)) {
        // quinzenal
        $type = 'fortnightly';
    } elseif ($da == 1) {
        // mensal
        $type = 'monthly';
    }
}