"I never got a chance to go back to graduate school. But in place of that, I have spent the last ten years learning things that are not taught in schools anyway - like when to abandon a fruitless line of experimentation; when to push your boss hard for what you believe in; how to accept criticism and let it make the final product better - and a whole lot of technical details of my projects that are confidential.
At the same time, you bring up a critical point. It is vital to keep refreshing your skills after you leave school. I am a member of SAE. I attend my local chapter's meetings, giving me a chance to talk to other automotive engineers regularly. Of course, with SAE membership, I have access to their publications, and I do leaf through them every month. Our company had digital access to all of SAE's publications, and I frequently consulted the SAE literature to learn about advances in emissions control systems. In addition to that, I have attended the SAE annual conference some years, and I have served as a peer reviewer for conference technical articles. Aside from SAE, my current company has offered the chance to take some short courses - on Matlab, Simulink and autocoding, for example - that are relevant to engine controls work. I have also studied problem-solving approaches like Shainin Red X and Green Y. Those are just a few examples. I take continuing education seriously. I want to take advantage of all the research being done out there to help with my own work."