Bikes can take so much dirt and grime before they start losing efficiency- and all that grease will stop the C.F. from corroding

Parts I never look at are the brakes. They get a wipe down where I can see but last clean-up of a bike and I looked a bit further. This was after a ride with mud on the road and I thought the brakes were binding but it was dirt build up between the forks and the tyre. That suggested to me that I strip the brake unit and the dirt was not peel off with a screwdriver--It was with a knife blade it was so encrusted.

Every year I strip the bikes down to bare frame and rebuild. Only takes a few hours to strip and rebuild but it is surprising how filthy bikes can get away from just sight. And you pick up the problems while still a problem and not a breakdown.