是的，您可以安排一个WP cron作业来循环浏览一个帖子类型的所有帖子，并执行检查/添加术语。但对于一个有数千篇帖子的大页面，我不建议这样做。

在下面的示例中，计划的作业大约每天运行一次-请记住，wp cron不是很准确，它只在您的站点被访问时计划下一个任务（请参阅this question)

// Scheduled job callback
function run_update_tax_cron_job( ) {
    $posts = get_posts( [
        \'post_type\' => \'your-post-type-slug\',
        \'posts_per_page\' => -1, // getting all posts of a post type
        \'no_found_rows\' => true, //speeds up a query significantly and can be set to \'true\' if we don\'t use pagination
        \'fields\' => \'ids\', //again, for performance
    ] );

    //now check meta and update taxonomy for every post
    foreach( $posts as $post_id ){
        $meta_value = get_post_meta( $post->ID, \'new_used_cat\', true ); 
        $new_term = ! empty( $meta_value ) ? \'used\' : \'new\';
        wp_set_object_terms( $post_id, $new_term ,\'vehicle_condition\', 
    false);
    }
}

// Schedule Cron Job Event
function udpdate_taxonomy_cron_job() {
    if ( ! wp_next_scheduled( \'run_update_tax_cron_job\' ) ) {
        wp_schedule_event( current_time( \'timestamp\' ), \'daily\', \'run_update_tax_cron_job\' );
    }
}
add_action( \'wp\', \'udpdate_taxonomy_cron_job\' );