With the BlueBuilt vacuum cleaner bags for the Wisberg B7000 (28 pieces), you'll have enough bags for up to 7 years. That's useful, because this way you won't suddenly run out. Replace the bag on time. This way, your Wisberg vacuum always vacuums powerfully. The size of your home and how often you vacuum determine how often you replace the bag. Usually, that's every 2 to 3 months. Note: you can only use these vacuum cleaner bags with the Wisberg B7000 vacuums.