Rear brake pads don't ordinarily wear out as fast as the front brake pads, but as surely as the rear wheel follows the front wheel ordinarily, the rear pads do indeed wear out (pics below). Story is that the left rear-pad became separated from the right rear-pad, or visa versa, and I just couldn't locate the missing side of the pair, and I wasn't about to order new rear pads and waste money on a part that I knew I had somewhere and so on. I changed the front brake pads a while ago. Just by coincidence, when I was about to change the front pads again, I found the missing rear pad so decided to do both front & rear brake pads.
However, the rear pads had less than a millimeter of meat left on them at this time. The edge of the rotor actually gouged the backing plate. Here, I'm glad that the metal that the rotor is made of is harder than the backing plate. Of course, the moral of the story is if you ever take one of the pads out of the cellophane package, be sure to put the pad back in the same package so they stay together. If you take two of the pads out of the cellophane package, rubber band the pair together. Wink.

Padding or lack thereof shows up better in this photo ....

Backing plate standing on edge. Anti-squeal plate removed.

