I find myself depending more and more on files lately and I'm tired of what seems to be the temporary nature of the local hardware store Nicholson file.   I'm wondering what brand people have found that last the longest.. and how you maintain their longevity. One thing I've been wondering... does the carbide face on some of the file guides destroy the teeth? My first impression is no.. because the carbide is so hard that the file teeth can't even bite at all.. so they just glide across. But s