All those little kid fly fishing kits and everything came with leader straighteners, so I brushed it off as some useless tool that I can better do with my hands. Well, many cuts later I have finally gone back and pruchased one myself. I was an idiot before! These things are great. Such a simple design/idea, but it really saves the pain on the river, literally.
I have been asked "why spend time straightening a leader?" Well... would you eat a fly surrounded by circular coils? Also, a straight leader will improve casting accuracy!