I have painted many times before, but usually only 2-3 rooms, not an entire house. The result is convincing, but the process was a nightmare. When you buy a paint that isn't cheap, but then doesn't cover well, or is way too thick, dries too quickly, etc., you get annoyed at your false stinginess. Today, I would gladly pay the extra 500 €, but work with professional paint instead. Such a STO bucket costs about 65 € as far as I remember, but you also make progress faster and need a bit less paint. It makes a difference whether you have to paint 600 sqm once or twice. In the end, your enthusiasm just runs out :)
Which paint I like to use: Max Bahr own brand with the green lid. However, I have only ever used it in rental apartments where 5 tenants had already painted before, and I usually only had to touch up a few rooms