If stored in a garage attached to a house. A battery post switch is cheap insurance. Just remember to use it. Preserving a car is also limiting the miles you put on it to some extent. Chasing everything down you find.

I have a 1984 300d I intend to keep up well and limit use. It has similar milage to yours and is really good overall. Other than it should be re painted unfortunately.

I assume some of the kids or grandchildren may get some of our cars. I also have a lower milage 114 coupe. To say these were less than desirable when I picked up the better example is true. I just like the way it drives and handles. It too has a pristine original interior. They are slowly becoming more acceptable.