Things that are not replaced on a schedule. Brake pads and rotors, for example. You don't follow a set schedule of either miles or time with them, right? Although you do with the fluid, or at least you're supposed to.

And I don't want to get into a thing, here, but I hope this makes it clear that "routine" maintenance is not the same thing as "preventative" maintenance.

But if it makes you actually DO the maintenance, then you can call it whatever the heck you want.