Wash Your Bags
A clean bag is a happy bag, may not apply to all inanimate onjects.
I worked for Electrolux, in the 70's as a door to door salesman. I would ring the doorbell and pray no one was home, so I din't have to go through the spiel.
Elux used a cloth bag to demonstrate the 1205 and later vacs. You'd vacuum a spot on the rug with owner's old cleaner. You would tell them to let you know when it was clean enough. Then I would take the Elux, vacuum the same spot, remove the cloth bag, hold it tightly to the floor and snap the handle on the back of the bag twice. Let the dust settle and remove the bag. There on the rug, to the complete horror and shock of the home owner would a nice oblong shaped pile of dirt, hair and debris.
We were told the cloth bag inbibited suction, paper bags were superior, and never to wash the bag and lint and other sediments would clog the cloth pores of the bag making it less efficient. Elux would not honor the warrantee on a new vac if you used cloth or after market bags.
The purpose of vacuuming is to remove dirt. The more suction you have, the greater your chance of deep cleaning.
The more freely air passes through the dirt in the bag, the higher the suction of the machine and the more efficiently it cools the motor, increasing the life of the vacuuum.
That said, what ever bag you use, CHANGE OR EMPTY IT OFTEN.
It isn't about how full the bag is. A quarter inch of heavy dirt in the bottom of a bag will stop airflow and function while a bag filled to the top with lint lets the air pass through.
I listen to the pitch of the motor, check the suction, as I am cleaning and if you have an Electrolx and adjust the suction control correctly (mid range) it will pop open and shut down the machine when suction drops, regardless of how full the bag is.
My daily driver is a Hoover Self Propelled Wind Tunnel. The air passes through the dirt in the bag as it creates suction.
I change it often.
I hate the smell of old stink, when the air blows through old dirt in the bag. Worse if you have animals and it blows the smell of old dog through the house while you are cleaning.
I am not at all sure washing the bag is the best way to care for it, as it removes factory finishes and changes the function of the cloth.
More than one bag is a cool idea. Turning it inside out and vacuuming it or brushing it, oustide and downwind, are highly useful.
What ever bag you have, empty it often. (LOL)
Kelly