The Nissan Path

What is the life expectancy of the fan clutch? This week at about 117,000 miles I'll be having the 3rd fan clutch installed on my 2006. It seems I have to replace it every 50,000-60,000 miles. Is that normal?
The first replacement was a genuine Nissan, and this one is too.

Check balance on your fan, even a tiny amount of imbalance out at the ends of the blades becomes very exaggerated at engine speeds and will cause repeated clutch failures.

I don't know where you're located, but counterintuitively, the more work a viscous clutch does, the longer it will probably last. That's because the speed differential between the pump and fan sides of the clutch is greatest when the engine is cold and the fan is freewheeling. Once the clutch heats and the fan grabs, the bearing surfaces inside the clutch do far less work. So as a pure mechanical matter, cold climates are clutch-killers (not that you can necessarily do much about that).

Well, going through old posts I found the original fan clutch was replaced around 34,000 miles, so it seems I actually got over 80,000 out of the replacement. So, thanks global warming

I can clearly hear my fan clutch roar occasionally when the ambient temps are very high. Engine temps are nice though.