Assessment of feasibility of construction project

Alright. To each their own. For me, age is simply still too far away mentally.

Our eldest currently uses maybe 4 sqm of his 8 sqm children's room. The shelf is still pushed to the end of the bed to avoid moving a single extra foot. And when they are small, 12 sqm is huge. I also never regretted my childhood in my 12 sqm room. It was sufficiently big and I never missed anything. But I was never given the impression that I needed my own apartment in the house. There is a sofa in the living room. If I had wanted my own, I would have had to manage with a sofa bed or just wait for my own apartment. But everyone sees that differently anyway. Plan primarily for yourselves. Only secondly for the children. You will have to live in that place your whole life. Your children will move out after roughly 20 years. You pay off the loan, not your children. And regarding size: I find 140 sqm completely sufficient. My parents built just under 120 sqm (plus basement) and that was more than enough. Now the children are out and they are thinking about what to do with the rooms.

And regarding the size: I think 140 sqm is completely sufficient. My parents built just under 120 sqm (plus basement) and it was more than enough. Now the kids have moved out and they're considering what to do with all the rooms.

I know that. My parents have 140 sqm plus basement. All the kids have left the house. Half the house is now empty. And they already have separate bedrooms.

And before I get into debt, the children simply have to manage with 12 sqm. Man, where do we live! What a sense of entitlement! Karsten

Everything has its advantages and disadvantages. Certainly, "younger" houses with rather large rooms are easier to sell than those with small ones. You just have to look at the statistics and quickly see that living space and room sizes have been getting larger and larger. I find our living area pretty average (15 and 16 sqm) and clearly one (at least) could have been 20+ sqm as well. Friends have a separate (~24 sqm) large playroom for the kids. That's really great. For me, that's luxury... but you can't have it all. When planning, we always considered a possible resale (also when choosing the location of the plot) and therefore paid little attention to the size of the house or the question of "what about in old age."

That is also a strategy. We are building for now and the near future (children very small). If the place is too big on day x -> get rid of it.

That is also a possibility, although I would point out that most people build or buy with the background of a worry-free life in old age. Since your means are apparently somewhat more extensive than those of many here, I won't take you as a standard. Apart from that, the location should play a role anyway, because at 70 even short distances become very long.