Good to know that a rotor can be this worn down and still stop the vehicle.  The only reason it was found was the caliper started leaking because it overextended the pistons and leaked.  I am thinking that it has another 100,000 miles on it, the more worn it gets the better it stops, right?

And I thought mine was worn out. I didn't get down to the cooling channels.

I've seen several of those. Hate to rub noses in this... But.... That is a sign of owner abuse and lack of vehicle inspection which should occur during you typical oil change. You should be rotating tire at your oil change while all 4 tires are off you should take the few seconds and look at the brake pads.

I agree with always wanting to check the pads and rotors at least every couple months. You would be surprised at how many people bring in rotors that look like that to the store here. I get at least a set or even 2 a month. Just crazy.

This is on one of the ranch trucks, it is a GMC Kodiack C6000, so tire rotation is nonexistent.  It is luck to get an oil change twice a year, whether it needs it or not.  We just bought the truck a month ago go or so, not saying that it is right, but maintanance is kind of on the when we get to it side.  The inside pad was dragging but did not produce any noise, so we did not know that it was that bad.  Heck, sometimes we tell the boss that our work trucks need something done to them and he says that we will get to in, then he has to drive that truck and says, wow, we need to get that truck in tomorrow to have it fixed, just good thing we are flat landers and do not have to brake going down hills.  LOL.