The skill set in EE changes faster than CAD software, unless you are in power engineering which is pretty stable from year to year. Beware of specializing in control systems, you could spend months learning a new system and it will be obsolete by years end. When I do a control system, I always figure it is the first and last time that particuliar technology will be employed.
I branched out into structural engineering about a year ago, talk about an unchanging science. My references include Theory of Elastisity, Timoshenko (1959). Some of these old methods produce results identical to an FEA model with 500,000 nodes.