Oh, come on, there is a perfectly black and white answer:
Change the fluid. No, don't change the fluid! Why change it? Because if you don't, the earths magnetic field may get out of alignment. But if you DO change it, then monkeys will die and fall out of trees all over the world! Change it. No, don't change it!
See, told you it was black and white
BTW - I'll be changing mine as soon as funds allow (dealer can do it), but that's because I don't like monkeys anyway....