Depends on what kind of stuff you have on your bike and the conditions you ride in. Chain, obviously. If you have cartridge bearing bb and hubs the bearings will need replacement every now and then. I never really bother with servicing them. Loose ball hubs definitely need service every now and then. Derailleur pivots? I keep my bikes really clean so they don't need it very often but a few drops of oil won't hurt. Headsets last ages if properly adjusted but the bearings need to be taken out, cleaned and greased...how often depends on you again. I never lube cables/housing, I just replace.
And of course this should not be in GD, it should be in the proper section which is obviously 'bicycle mechanics'. Come on people, stop dumping every thread you start in GD.
Last edited by cxwrench; 10-16-22 at 09:12 AM.