Winter is just kicking in here, so my 80’s annual underbody and chassis jet-wash will wait till spring, or at least till the salting stops.
I say annual, but it gets a few washes under there in between if I take it in the mud.
I hate to see any car with the customary “lifetime” of mud caked into every corner. I’m convinced it encourages rusting and rot, especially when saturated in salt water, only to be reactivated every time it gets wet, with or without further added salt.