After reading through these posts, I'm coming to the conclusion that it depends on what your media is made of. More solid [plastic?] media [Spring-flow, Matala, hair curlers, bioballs......] will tend to last longer as they won't break down as quickly. They might clog, but still they tend to be rinse & reuse. Whereas the other media like buffer pads and furnace filters are more fibrous and do tend to break down faster. Once they reach the end of their life-span [months, maybe?], they're history. At one time I used furnace filters, and it bugged me to death when they started breaking down -- it seemed like I had more debris from the filters than I did from the pond itself.