You see, I know an example in my circle of acquaintances where the construction was delayed by 8 months and the budget was exceeded by 20%, because, for example, the windows had a delivery time of 4 months, it was suddenly winter, etc. pp. If you want to subcontract a trade yourself, you have to understand it first – and I think none of the laypeople here fully do that – so you are dependent on the architect and if he is an idiot, you have just as many problems as with a bad [GÜ / GU]...