Here in the rust belt, where the DOT salts the roads to melt winter ice and snow, the salty water on the road gets into the 9000XL adjustment mechanism and causes rust. After a couple years, the rust will be so significant that the adjuster no longer works. Rancho adds NO rust preventative to the adjustment mechanism at the factory.
They will, however, warranty the shock if the adjusters stop working.
I recently had my 9000XLs replaced under warranty.
Before I installed these new shocks, I removed the plate that holds the adjuster knob, and liberally applied anti-seize compound to the adjuster mechanism and retaining ring, then put the plate back on and installed the shocks.
I plan to inspect and reapply seasonally as needed.
If you run these shocks in the rust belt, be aware of this problem
I don't know if the problem will be more or less significant in salt-air environments... but I think it would probably be worthwhile to treat the adjusters if you are gong to run them in HI...
HTH, good luck!