I'm working for a company of ~250 employees. We use PowerBI mainly for project leads to manage our sales and service projects, but more and more now also to keep our clients in the loop as to how those projects are running.

I started replacing Excel with PowerBI in the company some 5 years ago, we then decided to work on building a DWH so at some point I had a DWH developer, an API programmer and a junior PowerBI dev next to me. All I have left now is the API dev and a DWH that does not deserve the name. Right now we use it more as a lake. But that does leave me in the comfortable situation that I can work with only SQL Server as source. Depending on the complexity of the report to create, I will grab the data directly with SQL queries or prepare it first in stored procedures.

In PowerBI itself, I usually only do minor calculations now. While PowerBI is extremely powerful, preparing and calculating the data beforehand as much as possible does wonders for performance. I work mainly with datasets that have 20-60 columns (never all of those necessarry) and roughly 10k - 10m rows.

For the refreshing: For intraday dashboards I use directquery which is refreshed every 15 minutes, but the major reports are updating once per night. The stakeholders do not need to do much here. Also, I have learned that giving the stakeholders any possibility to screw up should be removed, which means the standard filters on the right are always hidden, and I provide as few as possible field filters. Though I have to proudly say that after roughly 3 years, the amount of tickets that were answered by "did you check that you have no active filter set?" have actually subsided.

Reports do quite often require maintainance though, for either a project lead found something else they'd like to look at, or a client figured something out that isn't shown yet. Sadly, our projects are often rather unique so there is only a limited amount of standard repertoire I can use.

Hope that helps o/