What do you mean how long do they last? They should last forever, you just need to clean them out every so often... My previous case had a filter in the front, but I ended up removing it because it was a bit too difficult to access. My new case, a Cooler Master, basically has a filter over the whole front. I think over-all the inside does seem a bit cleaner than my previous computers. I just take the front off now and then and blow it out. Or even taking compressed air and spraying it while the front's still on tends to clear most of it out.