The '05 Highlander needed new rear brakes and rotors because the pads had become stuck in the calipers. The cause was severe rust jacking under the stainless steel shims; which caused the shims to lift off their caliper bracket bosses, and the pads to get locked in place. They eventually ground and scored the rotors pretty bad. Time for new rotors, hardware, and pads.
This brings to mind the age old question of lubrication. Do you lube the caliper bracket shim bosses, or do you lube the shims (or both) when replacing pads? When using SS brake shims I was taught to lube the bosses only and keep to the shim dry. Adding lube to the shim will only make it gum up with brake dust more easily. Others folks insist on lubing the shim so that the pad can move more easily.
Looking at the old SS shim, not only did the rust jack the shim, but also started rusting the stainless steel. I would imagine in the salt-belt this would be an even more severe problem.
Bottom line -- lube the bosses to keep rust from ruining your rotors and pads.