[lefnire]

Agreed, but it can be balanced. Dedicate 1h/d to learning, no more. Balance that 1h w/ new vs current tech. Some technologies really _are_ a major investment; while others are smaller improvements than is worth sacrificing your expertise, as you pointed out.

I've had "1h learning" as a daily task for many years now, it's how I transitioned from PHP to Node. Shiny and hot, yes, but more importantly it's one language across all the work I do, and that saves me _tremendous_ amounts of time from when I was on PHP. That was a worth-while investment. Now I'm using Angular while React is getting hot. I'm not convinced that'll boost my productivity substantially, but I have that 1h/d to learn so why not? If it turns out to slow down my productivity compared to my Angular expertise, then I'll veer that 1h/d towards something else instead (VR + Unity is sounding super interesting, or maybe I'll explore this functional programming stuff everyone's raving about).