I would expect the hoses are getting porous. They are a dealer item.
Check your transmission hoses when you are in there, they have metal pipes that rust through. Generic hose can work with them.
I would not expect rust to be a major issue for your area.

Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.