replacing Brake Pads

specta wrote:
"IF" it gets contaminated.

That's something that I have personally never experienced.

While working in the automotive field the only time I saw brake fluid that was contaminated was when someone added something to the master cylinder other than what was recommended by the manufacture.

I'm not saying don't flush it, I just don't see it as a problem if you don't.

Pull the cover off the master cylinder reservoir, now compare that brake fluid to new fluid. The reason it's a different color and murky is due to contamination.