Your description of the issue does not suggest your calipers need to be replaced. Many franchise repair shops suggest calipers with every brake service as a “preventive maintenance measure”, and because they are an easy way to increase the amount of the bill. Your car is nine years old, so caliper replacement is not a bad idea if you are really anal about your car and don’t mind spending the money to ensure that your car gets the best possible brake system repair (if this is you, have the flexible brake hoses replaced too. They are cheap and often forgotten about until they burst, which is quite rare), but it is most likely not necessary.