Assessment of feasibility of construction project

Regardless of the size of the house / amount of funds... I imagine life in old age WITHOUT property but WITH proceeds from it, more carefree Maybe abroad, or a nice rental apartment or a nice condominium..or or or

I absolutely agree. Where does the goal come from to have to keep the house until death?
This also leads to the question of why a house should be paid off by retirement age.

But:
That's how I see it today. Whether after decades of emotional attachment I will still see it that way remains to be seen.
And moving from NRW to Mallorca in old age is not just something you do, regardless of finances, if the grandchildren are based in NRW.

I see it differently. First of all, man and woman are not the same age. Usually not, mostly they are five to ten years apart. That means, when the man retires, the woman is still working for a few years. The man is often quite glad to still have something to do around the house and garden. When both are at that stage, there is still a narrow window of time until the older one becomes infirm and no longer wants or can travel. She often takes care of him then. He usually passes away first. Now comes a point where she experiences a third spring and possibly sells, to live only in a supervised residential facility with full service... or the children take care of mom’s house and spare her the work. That’s often how it goes. Karsten

Our children have 26 m² rooms, so the Duplo train can stay set up for 2 days and some friends can still fit in the room.

Most moms prefer it when the children don’t have so much space that they no longer clean up

Never before have the "chances" been so high as today to experience unemployment even with a good education – which is, as is well known, a financing-threatening situation. At the same time, I get the impression that even more and more matter-of-factly, an increase of about 60% in the usual square meter count is expected when moving into homeownership.

Where does the goal of having to keep the house until death come from?
This simultaneously leads to the question of why a house should be paid off by retirement.

At least that much. Retirement has always been associated with a lower income than in the "active" years. Additionally, "old age" is today seen as a financing disadvantage: refinancing over 70? – the banker has to laugh himself down into the basement. Financing duration should never be longer than the holding period – this still applies when planning to switch properties.

Never before have the "chances" been as high as they are today to experience unemployment even with a good education – which is known to be a financially threatening condition. At the same time, I have the impression that even with increasing self-evidence, a flat rate of around 60% growth in the accustomed square meter area is expected when moving into home ownership.

Oh come on, are you serious???

I wonder why it is talked about here that the house MUST be maintained? As long as I stay healthy and everything goes according to plan, I will retire 8 years before my wife. Of course, the financing has to be settled. It is. And you can travel etc. even if you also do enough for retirement on the side. Which means that I finance in such a way that I am not constantly struggling and, in addition to the reserves for the house, also have money for a sensible retirement provision. But that often doesn’t work because the demand for new living space is sometimes huge. This is not a value judgment either, because people's life plans here clearly diverge. I just want to present my plan. And I see myself relaxed in an age-appropriate home that is paid off and able to indulge my hobbies. Then you take the 400,000€ from the proceeds (depending on the market situation and inflation) and treat yourself to nice trips and a retirement home in Thailand or something like that. I also think that’s good.

Oh oh, we must have made a mistake in planning. We have less than 140sqm and the children's rooms are 15sqm...