The way I see it people who just like to get a degree will complain about having to take classes with material in it they already think they know.

People who are really interested in the subject will not complain. I for example have been programming for the past 15 years and I will still read something like an introduction to C programming, just because there might be some ideas, explainations or examples in it that will help me deepen the fundamentals of what I already know.

Arguably there are topics where this works better and topics where this works worse. In electronics or mechanics groking the fundamentals is so essential to the whole field that you should know them by hard. And the only way to know them by hard is spaced repetition. So having some overlap in the things you learn is not only necessary here, it is crucial.