MB applied a wax to the latches around the car when it was assembled, they sell it in a small homeopathic medicine shaped jar and goes for about EUR 50/- in retail. the equivalent american version costs USD 2/-
its a little crayon type grease stick called "lock ease" and only a slight rubbing is enough - you can substitute it for a candle made with beeswax - usually sedans dont need it - the G wagens and sprinters yes - they are squeak and rattle boxes even when new.
I also use it between interior parts to prevent them squeaking and rattling.
anyway - regardless of mileage change out the brake fluid every year with any good quality fluid - even DOT3 works - its only difference is a slightly lower boiling point - wont notice unless you are doing bank robbery getaways. A good shop should have a pressure bleeder - if they dont then a pedal pump with catch bottle above hub level is good enough. A full flush takes 1 litre of brake fluid.
If the car is 10 years old - replace the rubber brake lines at the wheels.
For brake service only use silicone grease if required.