Hi Shotgun, If your file is well made and properly used there's no telling how long it will last. Some of my files are over 60 years old and others 40-50. A file is shot when the teeth are dull and it will not remove metal or it skips over the surface. A file should be used on material that is softer otherwise the edge of the teeth will roll and the file will not cut. I have my piece firmly mounted, stand while filing, use 2 hands on the file(one on the handle the other on the tip) and use firm even strokes. There are fellow hawkers who can explain it better than I can but that's it in a nutshell.