Just because I wanted to, I replaced the brake lines and calipers a couple years ago. This is a 1999 model with 80K miles on it. I mainly did it because I was worried about the old caliper slide pins sticking due to gummed up grease/dirt and the potential for the rubber portion of the brake lines to have deteriorated. I had no indication prior that there was a problem, but I wanted to have this done....... after the replacement, my mechanic showed me that one caliper showed indications of a sticking slide pin and the brake pad showed some irregular heating, and the hydraulic lines looked almost new. With that said.....I DO feel more confident now that those components are new and the braking system has been checked.
Like said above.....spend a little now for preventive maintenance and evaluations, and get peace of mind when you are traveling that everything is in as good a shape as you can.