You want to use your car for how many years?
Three years, NO.
More than three years, maybe. more than seven years, definitely.
If you car is AUDI, NO need, the body is galvanized. (hence the car is expensive).
If you live in an apartment with indoor parking, and if parking has water hose for you to wash the underside of your car (those SALT), then you may not need to (I once lived in an apartment and the underground garage has that water hose, for free).
Rusting is a Chemical reaction, and SALT actually speeds up rusting.
Decision is yours.
Good luck