What is the usual reason why blades are replaced or thrown away?
They will in time wear thin...
The back edge, lift wing will generally etch out and come off, especially in sandy areas.
Cutting edge will eventually be ground away during sharpening...
And occasionally they will get hopelessly bent damaged from striking something.
On a multi blade system, that uses staggered placement of blades, the length is needed for the necessary overlap...
the tip of the cutting edge is what does the majority of all cutting, it erodes away the fastest, once it is gone the blade will not preform like it should ...:smile:KennyV