Expiring vs. permanent skills
The article was about soft skills (a.k.a. interpersonal skills), but I most clearly see the distinction between expiring vs. permanent skills in my field of study, computer science + software development.When I look at what's hot - in people's blogs, in bootcamp classes, and in what people like to boast about - I see stuff like the React framework and Node.js and MongoDB. Having been in the industry long enough, I've watched these top trends change every few years.Meanwhile, what I learned in university is all the unpopular stuff but that which underpins the technologies we use today. For example: Mathematical proofs, regular languages and automata, time complexity, computability, balanced trees, assembly language, recursion, pointers, declarative rules, SQL, various subsystems of operating systems, etc. This stuff gets mentioned a lot less in popular discourse, but I find that my knowledge in these areas accumulate over time instead of going out of date with each new fad. Moreover, I find that this set of knowledge continues to help me understand and work with new things that come out in this field.