I've always been a fan of the Stronglight roller-bearing headsets, and 20 years ago when I built up my present commuter bike I put an A9 on and decided to see how it would fare without any maintenance. Today, 20 years later, I opened it up to take a look at the bearing races. You can see the results here:
http://www.os2.dhs.org/
All in all, I think it came out quite well. You can see a little bit of fretting damage on the lower race from the bottom set, but the rest of it looks perfectly fine. When I reassemble, I'll switch the upper and lower race sets and hope to get another 20 years of service out of it!
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-John Thompson (john@os2.dhs.org)
Appleton WI USA