Hi Lindzy and welcome along ! If there's 84k miles on the pump and you have no evidence that it has been changed in the cars lifetime, I would take the opportunity to do it now, as it would be at least 5 years old now ???? The reason that most garages recommend a pump change is because most are ran by the timing belt now and most timing belts are now in kit form and include new guide bearings, belt stretcher and some include the pump and gasket, when the new belt is fitted the new stretcher puts a different tension on the belt (because it is new) and this may be more than the old belt, which is a different push or pull on the old water pump (if it hasn't been replaced) what often happens is, that 3 or 4 months after you replace the timing belt and don't renew the pump, the pump begins to leak because of the different tension Apologies for the rambling response, your eyes have probably glazed over