Do you do your own class or skill testing in your favorite game, or do you make use of theorycrafters and their research?Here's my approach to class builds and rotations:
I take a first pass on my own, making my own build and rotation. Then I go to the theorycraft sites and see how and why their optimum build differs from mine. Usually I'm close, but I've misunderstood exactly how some abilities work. Or perhaps I miss a combination of abilities or another trick. Finally, there are some results which are just plain counter-intuitive, but fall out from the math, and get proven by parses. Seeing the "optimal" build and reasoning explains what I don't understand correctly.
Sometimes the theorycrafters value something higher than I do. For example, I tend to prefer passive abilities over active ones because I'm not good at hitting abilities perfectly, so an ability that's always on often works better for me. Fewer buttons for the win! But very good edge players often prefer the control given by the active ability, and are good enough to weave the extra button into their rotation seamlessly.
I think this approach is better than: a) not checking and unknowingly using a suboptimal layout; or b) blindly copying whatever Elitist Jerks or the forums say. Making your own build first, and then checking for differences leads to a stronger understanding of the game as a whole.