I was insanely anal about changing the fluid, did it at 30,000 KMs (18,000 miles), again at 60000, and again at 100,000. Mine kicked the bucket at around 120000. On teardown, the fluid came out clean as the day it went in, minus the big chunks of gear teeth of course :-) I've been driving manual transmissions for 20 years and I've never had a problem. My Xterra transmission was a lemon, plain and simple.