Like many others, I have held onto my Shop-Vac pleated filter for too long. Yes, I cleaned it thoroughly, but over time the filter's "paper" folds fill up with microparticles that cannot be removed and airflow suffers. You just don't notice it because it happens slowly over time. When I installed this new Yweller 90350 filter cartridge I was amazed at how much suction was increased. It feels like he can suck a golf ball through a garden hose (+: