I was thinking about Bingley’s idea of sharpening blades — I have the ability to sharpen knives and these aren’t much different.  Then I had a cup of coffee and looked at LCranston’s math.  Next time I’m at HD I’ll buy another   
50 blade dispenser.  The idea of sharpening a throwaway blade covered in tape/glue is just not interesting.  Blades are cheap.