Most Mercedes-Benz of the 1990s and 2000s were well protected from corrosion. There were certain years (Daimler-Chrysler Years) where build quality wasn’t as sensitive to rust as others, but regardless of the year your vehicle was produced, protection from rust is essential.
Salt and dirt on the roads will latch on to you’re the inner side of your wheel arches, to the undercarriage and primarily to places that you cannot reach without a ramp. With your vehicle now between 20 and 30 years old, it could require an update to its protective coating. Areas that may need attention include the subframe, differential, hydraulic and brake lines.