Today is 'prinsjesdag' in the Netherlands, the day that the queen reads the 'troonrede' with the governmental plans for year to come. There's a ceremony that a golden carriage takes her through part of the Hague to the place where she reads the plans.
I didn't know that all schools in the Hague have a holiday on that day! Something which is common knowledge for the habitants of the Hague. Not a big disaster, but you have to arrange child care or be at home etc. I learned about it through the schoolcalendar.
It made me think about the enormous importance of being able to access relevant explicit, local knowledge when professionals are more and more working on a variety of jobs and change jobs. When I lived in Den Bosch, it wasn't very important to know that schools in the Hague are closed. But when you move here, it's part of the necessary brain-luggage of a parent with school going children. So rather than knowing a lot, it's better to become good at accessing the most relevant information - and distinguishing between relevant and less relevant information.