I feel both ways about the C bag.
In an average home, the C bag is just large enough to last one month, and it makes sense to change your vacuum bag about once a month whether it is full or not. Nobody want to store quantities of old dirt. IMO the filtration is not as bad as some will lead you to believe. Im thinking about the original Hoover Company bags.
On the other hand, having used the C bag in a commercial setting for some time, I will state the obvious and say the C bag is a poor choice for high traffic or commercial settings. Fine powder, like road dust, will clog it every time. And if you change the bag according to the package instruction you will just about always have some dirt spilled. Sometimes just a sprinkle, but still a spill.
