I just started my Filstar the beginning of April. The sponges don't show any wear yet, so don't plan to replace soon. The white filter pad crapped out a couple of weeks ago, but I started using polyester fiberfill in addition to it, so just increased the amount. The first basket has sponges, and the second has some biostars..and I fill the rest of the basket with polyester fiberfill. It takes a coupld of weeks for that to clog up enough to affect the water return, and then I take everything apart, clean it and pitch the fiberfill and put in new. It's cheap, I use the craft stuff from Walmart.