Single-family house floor plan 175 m2 - improvement suggestions?

but then not standing in front of empty rooms in old age.

They can be well used with the new hobby in retirement and for the grandchildren’s guest rooms. With three children, quite a few grandchildren will come, and then the rooms can also be used. To me, all this is too narrow-minded and not thinking outside the box... but I also find the discussion a bit one-sided. Regarding the apartment designs: Hallways too dark without daylight. No wardrobe, no possibility to place a chest of drawers or cabinet for jackets or shoes. Living room relatively large in relation to the rest. Bedroom hardly furnishable with a double bed/wardrobe. Dressing room on the upper floor offers no more than 3 meters and thus no added value. I just noticed: RBM 3.00... so not even a 3-meter wardrobe is possible. Later apartment upstairs without an exit. No guest bathroom upstairs. Where is the laundry washed? The window seat is also not a quiet zone, which it should be.

I'll write it again now because it was deleted.
[Hier ist Hopfen und Malz verloren.]
Someone has pointed out everything to the OP x times, but they are 0.0 interested.

Unfortunately, I can only agree. And, to make matters worse, the space program could probably be created with some fewer sqm without fixing on possible age variants .. in other words, saving costs. The question block regarding this is unfortunately not answered.

I don’t understand again why everything is torn apart so unfriendly. That is a common single-family house floor plan, isn’t it? At least if you remove the wall behind the stairs and possibly rotate it. I have seen that many times (also in real life) and it all works well. The isolation of the stairwell can be added in case of need in 20 years. By the way, the stairs in your plan are very generously designed, if I interpret that correctly. 110 or 120 wide?

Remove the wall behind the stairs, put proper windows into the "stairwell", make the living room smaller than the kitchen-living area, connect the utility room with the storage room (access then from the former storage room), move the utility room opposite the stairs and place a wardrobe there (like in floor plan 1 here).

Why so negative – that’s exactly what I have been thinking all along. We built similarly, although with a few more square meters. We have two tall narrow windows in the stairwell and in the wall between the stairs and the hallway on the upper floor an opening in the wall. This can be permanently glazed if the floors are ever meant to be separated. Space for a coat rack is indeed scarce with this floor plan. You would have to give that some more thought. And when people always say: build for now and if you can’t manage the stairs anymore, you can’t live in the house anymore. That simply isn’t true. I think that’s way too short-sighted. My father-in-law can no longer manage the stairs. He lives wonderfully on his own. In the morning the nursing service comes for showering, etc., and he moves around the house with a walking stick or walker. In the afternoon my sister-in-law comes by and keeps him company over coffee and cake. A cleaning helper has been coming for 20 years (back when he and his wife were still doing very well). If he didn’t have a (former) guest room on the ground floor, he really wouldn’t be able to stay in the house any longer, but as it is, it still works quite easily.

The floor plans you showed do not have some narrow spots.

It already starts with the fact that there is space for jackets.

The ground floor is not suitable here. A walker does not work. The bedroom does not fit a double bed. And so on.