I have a 6 or 7 year old bike with DA 9 speed components. I've kept the bike well maintained but have never done anything to the DA hubs. Should I grease, rebuild, or do anything else to the hubs? If so, how often or after how many miles should this maintenance be done? As far as I can tell they function ok although how would I know that they weren't other than noise?
Thanks

regrease... couldn't hurt.... if u wait until u hear a grinding noise its too late to save the bearings/cups.... keeping the grease clean will expand the life of these parts...

clean the hubs real well before re-applying grease...

should be good as new.

I have a 6 or 7 year old bike with DA 9 speed components. I've kept the bike well maintained but have never done anything to the DA hubs. Should I grease, rebuild, or do anything else to the hubs? If so, how often or after how many miles should this maintenance be done? As far as I can tell they function ok although how would I know that they weren't other than noise?

If you remove the wheels from the frame, remove the quick release skewers, and turn the hub axles with a "light touch" of your fingers, you should be able to tell if the hubs are in good order. They should turn smoothly with no gritty or binding feelings. If the wheels have sat in the garage for 6-7 years, then they may not need any maintenance. If they've been ridden regularly, then a clean/grease is DEFINITELY in order.