I'd like to somehow generalize this advice. My take is to compare proactive vs reactive learning. Early in my career I was all proactive learning. I would stud

I'd like to somehow generalize this advice. My take is to compare proactive vs reactive learning. Early in my career I was all proactive learning. I would study languages, frameworks, tools, anything under the sun. Vast majority of these I never used or got any value out of. As I became older and had less time in my hands I had to become more tactical with my learning. I started to switch from proactive to reactive learning. Reactive learning is learning new things in response to on-the-job needs. Does my new team use Spark in Scala? Let's learn about those then. I still like to keep a thread of proactive learning where I do more exploration, just to expand my horizons and have some fun. Still I'd say nowadays my ratio of proactive vs reactive learning must be around 20/80%.