Thanks to the Bluebuild vacuum cleaner bags for Numatic, you won't have to worry about buying new vacuum bags. With 28 bags at home, you'll have enough for the next 7 years. You should replace the vacuum bags every 3 months, depending on how often you vacuum and the size of your household. Make sure to do it on time, as a full bag can affect suction performance. This package also includes 7 filters. You should replace your vacuum cleaner's filter once every six months. This way, you keep the environment clean. Note: These vacuum bags are only suitable for Numatic vacuum cleaners.