Built-in kitchen with financing possible?

If you do a proper expense and financial plan and stick to it disciplinedly, you won't get into trouble in the end.

I think you’re never safe from surprises. That’s too general for me, to say that anyone who ends up falling short simply planned wrong.
For most people, it’s the first and only house. You gather many experiences only along the way. Yes, with the super-knowledge – or with the knowledge you have after construction, you could certainly have done the calculation better... but who has that from the start? Sometimes you don’t even have that if you hire a professional for it.
That’s exactly how it was for me, in the end I could have written the calculation correctly because then I knew which defects in the existing property hadn’t been noticed, which items had "slipped through" and which popped up like the devil out of the box, and where I had still gone for an upgrade. It was a bit of everything, and overall I felt the same way as writes. That’s why I still have to wait a bit for the terrace covering...