In my oppinion
I think that the "bag needs change" indicator is rather like one's car oil level indicator, when it comes on it usually is too late and there has already been some damage done to the machine. Rather just check it on a regular basis like checking one's oil and water on a regular...
Miele with bag
Hi I would like to comment on the issue at hand, I currently have two Miele's both with hepa filters and one being a cat and dog canister.
I have not seen that kind of dust in either one of the two and can only go so far as to say they are incredible machines. Have not tried...