Calipers Apply the brake pads to the Rotors always being used getting hot and cold.
Its hard to say how long they last some people are easy on there brakes some people like to use there brakes and turn those rotors a bit blue no mater which one of these people you are a seized caliper has a couple of warning signs.
You might get some bad smells from the tire being affected, squeaking, pulling to one side, pad getting worn uneven or too quickly.
A bad caliper needs to be replaced its not a hard job on most cars, half hour each caliper would be plenty of time at Greg The Mechanic 
On many cars and trucks the brake hose is held in place by a steel bracket as seen in the photo.
Well I’m going to give you a tip RUST GROWS in these brackets and Blocks the Flow of brake fluid.
I have opened these brackets many times and found the caliper is not the problem but the rust growing on the bracket is so before paying for new calipers make sure the hoses work to supply those calipers with the fluid they need.
