Man I am hitting 80K in 9 miles and have not changed my rears I have changed the fronts like 4+ times and I have had either 33's or 35's on it since like 10K I should change them just for the hell of it!
my '88 ranger had over 200K on it when i traded it off, i bought it at 98,000 and never did anything to the rear brakes besides pull the drums once in a while to confirm if i still had lining. my '93 needed rears at around 90,000. drums were stuck on so bad i had to bust them with a really big hand sledge. so i got the "china drums" and new rear shoes. ive put 2 sets of fronts on since ive got it. neither the '88 or the '93 had threaded holes to help pry the drum off, ive seen a couple of import cars that had that though. i anti-siezed my axle flange before i put it all back togther, should help.