You think doctors/nurses do homework? They go to paid courses/conferences all the time to stay up-to-date on the latest medical techniques. Hospitals have entire teaching departments for that kinda stuff. Why should it be different for engineers?
My late father was a physician and he absolutely stayed up late doing homework. He'd study for hours before an usual case.
I remember as a kid helping him swap out the latest updates to these massive binders of the latest and greatest info in medicine, which were expensive subscriptions he paid for. They'd send sections of text and instructions on what pages to remove and replace with the update so you'd always have the most current information.
Now we have web-based solutions that do the same thing, and they're often not free, either.