I did my brakes, Ford F-150 this year, and 08. The impression I got was that basically the replace your brake fluid thing was a scam. In certain extremes if it boiled, or you immersed your car in a flood, well sure. When I bled my brakes the stuff coming out looked like the stuff going in. If you know the history and performance of your car, then you aren't taking a risk to leave well enough alone. Now your dealer, what does he know. It is safer for you (if a non participant in maintenance) to just replace it, and he gets the cheese to boot. But the experts were suggesting flushing it all out was pointless.
Here is where I went wrong though. I did the front rotors and pads a year or so back, and they were still pretty new. I couldn't get to the US for some cheap stuff, so I paid a huge bill for parts alone, what it would have cost 10 years ago to get it done at the dealer, interesting that, they have returned to what they figure is our tolerance. This spring my wife was driving along and the brakes seized and overheated. I had to do the whole thing, pads rotors, and calipers, because the calipers seized. From now on, I will do all 3 at the same time. It costs an extra 50 in parts once the cores are returned to do the calipers. And it is about the same, or easier to do the calipers at the same time.