Yagni originally is an acronym that stands for "You Aren't Gonna Need It". It is a mantra from Extreme Programming that's often used generally in agile software teams. It's a statement that some capability we presume our software needs in the future should not be built now because "you aren't gonna need it".
On the surface, the world of agile software development is bright, since it is now mainstream. But the reality is troubling, because much of what is done is faux-agile, disregarding agile's values and principles. The three main challenges we should focus on are: fighting the Agile Industrial Complex and its habit of imposing process upon teams, raising the importance of technical excellence, and organizing our teams around products (rather than projects).
No matter how many screen sizes our artboards account for, some user’s browser will break loose from our prescription. With users resizing, rotating, and zooming the screen, new devices stretching, squashing, curving, and cutting (e.g. the speaker area in iPhone X) the screen, the sizes become infinite. Good luck making an artboard for each one of them.
Artboards are a lossy format. Using artboards in a handoff is a lossy process. When we pitch a finite number of plans against an infinite number of situations. We inevitably get in-betweens. Once there are in-betweens, there are unknowns. Once there are unknowns there is guesswork. Once there is guesswork, there are surprises. Engineers take the path of least resistance. We are ones who paved the path.