There are always approximate values of construction costs floating around ... about 2000 euros per m2 of living space, for example. Is this price set if you have everything done by companies for a turnkey house in the upper-class range? So not luxury but also no standard fittings, switches, doors, etc.? Do you think you can "earn back" a small basement through personal work for a 125 m² house? For 125 m² from the base plate, it would be 250,000 euros. If you now want a basement for about 35,000 euros... would you still somehow end up at 250,000 euros if you do the electrical installation, underfloor heating installation, sanitary pipe installation, etc. yourself? Or is that very optimistic? Thank you