My road bike is so clean you could eat your dinner off it.
But my TT bike which sits on the trainer in the garage all its life has a thick coating of cheap MTB wet-lube which i sometimes look at in disgust… but never quite get around to cleaning. If i spin the cranks it’ll move about 1/2 turn - i figure the watts i’m having to add to overcome this dirty drive train is a good thing and when i eventually clean it i’ll be flying along and my measured FTP will go up 20W.