i think my FX5 has been up and running for a little over a year. we had a snail infestation in that tank and they all got stuck in the filter, so we had to replace the filter pads then, the snails were feeding on it.. i think that was about 4 months later. and then i just changed the filter pads in August of this year. but.. i washed out the pads and they will be reused.