I think over-specialisation is potentially dangerous so it's worth bearing in mind. Ideally I think a balance is necessary, have one or two areas you focus on a

I think over-specialisation is potentially dangerous so it's worth bearing in mind. Ideally I think a balance is necessary, have one or two areas you focus on and keep your other, perhaps less developed, skills sharp. This is why I'm keeping a closer eye on things like Terraform and aws these days and generally sharpening my infra skills. Perhaps the best way of summing up my approach is to aspire to know everything about something and something about everything. The former gives you the satisfaction of deep knowledge, and the latter means you can pick up new tech more easily. Generally our industry is about knowing just enough in many areas, and knowing which questions to ask / what to search for. As for specific languages, as long as you're aware of a couple of paradigms, eg OO and FP, I figure it's not that hard to switch. Once you've mastered one or two languages you can generally be productive in another relatively quickly. We don't necessarily hire Scala devs for example, just engineers we think we can train up. I'm lucky in that the Scala job market is hot in London but I'm fully prepared for that to change one day. I'd probably target Kotlin or Java jobs if that happened but also open to anything interesting job-wise that will have me. I have my tech preferences but if I need to switch, and someone will allow me to learn on the job, then fine!