My factory pads have 45K miles on them, and amazingly, they are not making any horrid noises (none at all actually), and stop the car only
slightly worse than when new.
Mine probably have even less material on them than those above, and yeah, they have got to be changed out, SOON! (Along with a full fluid flush.)
I am guessing that the only thing which has allowed them to last this long is that I always press the ESC/TC button for the full allowed shutoff of those nannies every single time I start the car, right from new delivery, even in bad weather.
(I do mostly in town/not highway miles now.)