I am ashamed to say that this filter has never been changed in my vacuum since I bought it 20 years ago. I looked them up at Sears when I was there and they never had them in stock. In order to . it was not done. Finally I decided to take it seriously. It took me a while to find the right filters, but I found them. Now I have a nice clean filter in my vacuum cleaner. It was pretty easy to do. easier than i thought. No more excuses! They don't even cost that much.