If you have a pulsating on stopping is an indication they are warped. They would have to be checked with a micrometer to tell if they can be resurfaced.
There will be a pulsating on braking.
There is a pulsating on braking.
Yep.
Grinding
Visual inspection with outside micrometer. They should not be glazed, pitted, or thinner than the allowable minimum as measured with the micrometer.
could be bad rotors, or brake pads wearing unevenly, which would result in bad rotors.
Bad rotors
No just the bad one.
If you have a pulsation on stopping the rotors are warped. They will need to be checked with a micrometer to determine if they can be resurfaced of discarded. The government set the regulations.
what do brakes look like when they go bad, how far can rotors go?
You do not rotate rotors. Replace a bad rotor or have it machined if possible. Never rotate them to another wheel location.
if your rotors r worn you see little groves on them that go all the way around these grove tend to have a rust color