....Even experts do well to periodically recalculate their compartmentalized knowledge.
True experts actually don't need to do this, as they are always up to date. HB who completed their master craftsman certification 30 years ago and have remained at that level, on the other hand, are likely to have considerable problems.
At least a master student has been taught the theoretical knowledge of what static and dynamic pressure are, which a layperson with second-hand half-knowledge would hardly manage. Whether the master student actually applies and implements this is a completely different matter, since "stinginess is cool" usually determines the overall framework!
Many problems are home-made,
caused by the clients, not necessarily due to the specialists!
A technically correct, complete planning/dimensioning must therefore always be a few hundred € more expensive than without it. A technically competent HB loses orders because the competitor does not offer this. So why should he do it? Better to have an order, even with imperfect planning, than none at all, especially since contract contents do not obligate to energy efficiency or low consumption costs! Therefore, no reproach can be made against him. This technically correct system builder has absolutely no chance to survive in the market, as it is dominated by cheapness!
As a result, one finds in energy-saving ordinance or KfW 70 buildings sold by general contractors/primary contractors, AWP as heat generators even though they are usually completely unsuitable. With gas condensing boilers, nonsensical hot water storage tanks are usually sold for the sake of polishing numbers, even though they are usually uneconomical in the single-family house sector.
In the end, however, everyone gets what they really deserve!
v.g.