Our house is listed as a historical building, exactly as all the other houses in the historic city centre of Hornburg. We have to preserve everything on the outside of the house (facade, windows, roof etc.) and if we want to make any changes, we have to make a building application and get the permission of the State Office for Historical Monuments.
Inside the house, you can change, rip out, destroy whatever you want to. Of course we don't even think of that! On the contrary - we'll restore a lot in our old house (wood floors instead of the laminate the previous owner layed, just to give you an example).
Right now we are thinking of classifiying the inside of the house as a historical monument, too. All the changes we want to make are exactly what the State Office suggests anyway, and IF the inside is listed, you can get a lot of valuable information from the State preservationists for free.
And you can set off all the costs for renovations against tax liability. We tried to figure out how much money we could save thereby - it would probably be an amount between 10'000 and 15'000 Euro. Sounds good.
On the other hand, everyone tells us we're completely crazy because we'd allow the State Office to intervene in our renovation plans. And that we'd never again be able to sell the house if the inside is listed, too. Or for a lot less, which is of course an argument.
And even IF we decide to have it listed, it's not sure it will be classified as a historical monument by the authorities as only few of the original structure (end of the 16th, beginning of the 17th century) is left after centuries of rebuilding and adding changes to the house. I'll post pictures of the parts that are most of all worth protection over the next few days, but we're basically talking of the cellar and the attic, some of the doors and door frames and parts of the stairs (still hidden away underneath newer layers).
We really don't know what to do - any of your advice and opinions would be much appreciated!