Yellowbryk's windows are custom-built to enable stretch-to-fit. When modeling existing conditions, you will appreciate the productivity boost. When modeling from an AutoCAD background, pick-to-place the walls, then insert these instance windows and stretch them to fit the drawing.
If you were using Out-Of-The-Box (OOTB) families, you would have to create a new type for each size. In contrast, these families are streatchable in both plan and elevation views.
Our skilled Revit family builders were even able to create instance windows for those diffulcult shapes: Hexagon, Octagon, Triangle and Trapezoid windows.
You can purchase individual windows or get the whole set at a discount.