Weak argument. You just ask them upfront for the cost or at least brackets. They can act however they want after adding to that cost. You asked upfront, were given the amount and that's what you can pay. Otherwise all you are doing is letting peer pressure drive your actions. Also, a fear of surprise charges is about as much of an excuse as anything else. You are risking a lot by not doing a checkup in so many years, and "surprise charges" isn't a reason to not do it.