I think it is nice to have a basic understanding of differential pairs and impedance, I will admit I never really had to do the calculations since the ecad soft

I think it is nice to have a basic understanding of differential pairs and impedance, I will admit I never really had to do the calculations since the ecad software I use has several tools for routing differential pairs and even analyzing signals for impedance. But as long as you keep your traces really short it normally doesn't matter.