Learning something new usually makes you:
- Learn something new
- Notice that there are several things that you didn’t know that exist and maybe you should learn about it.
So when you learn something, you find it useful and end up using that knowledge, you’ll probably missing more pieces that could make that knowledge not so infalible (or not the optimum tool for specific situations).
What to do about that? Critical thinking. If you learn that X is a better alternative than Y, and end up learning X, find some time to learn Y too. You’ll find something useful there.
TL;DR, I’m learning about rails and, after years of thinking that dynamic languages and Active Record were not really the way to go… they are quite fine too.