There's no cleaning pad with the Katadyn Hiker Pro. It's a paper filter. The indicator to changing the filter is when it suddenly gets much harder to pump. That says the filter is full and you're having to really force water through it. How quickly the filter fills really depends on the water you're filtering. Muddy or silty water will clog it up pretty quickly. All that being said.....I get somewhere around 600-750 hiking miles between filter changes. Seems to occur about the same time I change my boots!