the first few uses. But if you have pets that shed, the bag will fill up pretty quickly and the exhaust will start smelling like dog hair even if you have a HEPA filter etc. So while they work well, be prepared for a swap. them quite often. Maybe every few months. Also, these bags will not fit some new Kenmore models. Our bags are too long, even though the vacuum cleaner is 5 years old. These pockets can have 2-3 inches of "depth" that is never used because they can't slide out far enough in the newer Kenmore models. They kind of fold backwards. But in general it's worth buying. and probably cheaper than what you get in the store.