But a lot of them DO lose airflow, which is what moves the dirt from your carpet to the dirt receptacle. There will be plenty of SUCTION right behind the CLOG, at least until the motor burns up due to lack of AIRFLOW. When filters get coated & saturated with fine dust, the vacuum WILL clog, no matter what some blokes might tell you. Bagless ones are the worst for this (especially if you don't clean the filters after EACH USE as the instructions tell you), as we un-clog hundreds of them a year – EVEN the ones who lie and tell you theirs will never clog!