I listen to the sound
of the exhaust on the Olympia. That's my daily driver. I can just hear by the amount of air flowing through when I want to change the bag. Sandy's right, bags are cheap. On my vintage machines, I have nothing but unused bags in them, and I don't use the machines to pick up dirt after I have rebuilt them. That's not to say I don't run them, just don't pick up dirt. If anybody saw the Olympia, you would think I was a vacuum cleaner abuser, and rightfully so. As a testament to Electrolux quality and durability I really USE that machine, and it has held up pretty well. My other machines have done their time and deserve a rest. I DO like watching an LX spit that bag out though, so I made one out of a new Lux bag, lined it with cardboard and plastic so no air gets through it, load it in the cleaner just to watch it come right back out!