-> RJT> This makes me wonder what's to wear out in one of those? 

-> My first guess would be spindle bearings since that's in
-> constant use and a mechanical device. My next guess would be
-> that the LED used to power the laser begins to 'wear out'
-> whatever that would mean for an LED? 

 Reduced "Lumen" output. While LED's have a very long life their output
does decrease with use.                               
 Rembember the Conversion of Incandescent Light Bulb to LED stop lights
some years back?
I see a number of Stop Lights now with Bad LED's in them.
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