I bought these filters as spares for a cordless vacuum, but the one that came with the machine seems to last a while. The filters can be easily removed for cleaning and simply reinserted. It dries within 24 hours when I wash it, depending on where others live it may take longer. Now that I have so many I just replace one with something that washes off as it dries. If I had to do it all over again I would only buy 1 or 2 extra filters, 5 is really too many if you don't use them every day.