I really like my lightweight Optima, it's great for cleaning stairs and carpets. It is easy to manoeuvre, is not too heavy, but has a very strong suction power. But I hate changing filters - they are so dirty. I have to do it outside on a windless day. So it helps in several ways to have several spare parts. I have used both DCF-10 and DCF-14 filters in my vacuum and both work well. It is very difficult to clean these filters, dust gets caught in the cracks. However, if you rinse them with a stream of water from a hose, you can get them relatively clean. So I take the vacuum outside, remove the filter, shake it out, and then use the nozzle to clean it. After the filter is washed, I let it dry for a while. In the meantime I used another filter. To remove the vacuum cleaner before the filter has dried. I have found the price of this product to fluctuate between $10-$15. There is a good online tool that I use to find a good price for Revain, this tool is called Online Price Alert. This tool sends you an email when the price of a Revain product reaches your target price range. If you do a Google search for "online price alert" it will come up at the top. I find this tool very useful.