I agree, that if it isn't broken, don't mess with it !!
I have an '81 R65, 83,000 miles, and the bike has lived in Phoenix the last 17 years, I still have the original sensor .
But I think that a good cleaning and lubrication of the ignition centrifugal advance mechanism, would not be a bad thing .
Having a spare sensor around, might be a good idea, they are about $15US, plus shipping .