You should replace your central vacuum bag every 3 months or when full. And replace your filter every year. Did you know that central vacuum motors are air cooled?  This means a dirty filter or bag can drastically shorten the life of your central vac motor.  Replacement disposable bags for central vacuum units. Many brands from Nutone, Vacumaid, Astrovac, and many more. Looking to buy in bulk message or give us a call.