User Defined Functions (UDFs) in Power BI - Three practical ways to put it to use
If you have ever written the same DAX logic in five different measures and then had to update all five when something changed - you already know the pain this feature solves. User Defined Functions, or UDFs, let you write a piece of logic once, store it in your model, and call it like any other built-in DAX function. Cleaner models, less repetition, and a much easier life when business rules change.