At work, I learn what I see is coming down the pipe for the next few years. I've been reasonably successful at my job because I have enough experience to see what senior management is worrying about. And I learn and focus on those areas.
I might want to learn something to get a job, I might want to learn something to make something easier…
But lately I’ve been leaning strongly in learning because I’m curious and it looks fun! The reason for it is twofold, one is that the motivation for wanting learn something deeply affects how you learn something and how much you get out of it. So, when I’m curious and I’m having fun, I learn the most, I enjoy the process the most, and I’m the most productive. The second reason is that predicting the future is really really hard and learning something because one thinks one should doesn’t really guarantees that it’ll give the results one expects.
It’s been quite often that I learn something because is fun or I’m curious and it later turns out to be useful in a way I totally didn’t expect.
An example is that I learned about finite state machines in a digital design book just because I was curious. Years later I got assigned a project in which a quasi state machine architecture fit perfectly and is one of the projects I’m the proudest of in my career.