How often do you change your Front/Rear Differential Fluid?

wnjj wrote:
Fluid may be "cheap insurance" but you're slightly increasing the risk of failure. What if you make a mistake when changing it? E.g. Wrong level of fluid, contamination or create a leak. Some things are better left alone for longer periods.

What? I'll change mine when I replace my transmission filter and adjust the bands at 30,000 mile intervals. I already have a cast aluminum differential cover with drain plug and full synthetic. Fear of doing simple maintenance just isn't in my wheel house.