Change Trash Auto-Empty Days

<?php
// Filter the stored option so the value takes effect for the trash cron job.
// Change 7 to however many days you want trashed items to survive.
add_filter( 'option_empty_trash_days', 'scseed_change_trash_days' );
if ( ! function_exists( 'scseed_change_trash_days' ) ) {
    function scseed_change_trash_days() {
        return 7; // Days before permanent deletion; set 0 to disable trash entirely.
    }
}