Bubba wrote on 04/16/13 at 09:04:24:^agreed...unless you suspect something different...I replaced mine at 11000 and even then I probably had about 3mm to go (riding hard) but since I was in there I replaced it...
+1
I just did mine this spring at 20,400 mi - the plunger was out, but not all the way - I would have said about 1/8" or more to go.
It actually didn't take that much time, I was able to save the gasket, so not really any money either.