You don't have to learn everything.
It seems like every week theres a new hot front-end library or framework. Its easy to feel like you need to learn everything to stay relevant when you're a front-end developer.
When I first started learning front-end development I spent a lot of time feeling stressed out trying to learn everything. I felt paralyzed and overwhelmed trying to read and watch every tutorial I could find. I didn't have time to actually build anything because I was trying to learn everything. I retained very little and mostly just succeeded in stressing myself out.
The truth is you don't need to learn everything.
The most important thing you can do is learn the basics. The basic skillset all front-end developers should have are HTML, CSS, and JavaScript. Everything else is built from these technologies.
Learn the Basics
Learning vanilla JavaScript and CSS will always help you. Despite all the buzz around CSS in JavaScript you still need to know basic CSS. Also React is really just plain JavaScript with some additional functions tossed in. Even Sass/Scss is basically just CSS. In fact if you replace .css with .scss as the file extension you converted your CSS to Scss.
If It Works Stick with It
Its easy to buy into the pressure to update your projects to the latest buzzy framework. When a new hot framework emerges there is always a frenzy of developers rushing to update their projects.
Don't risk breaking your production sites. Chances are visitors to your site don't know or care what framework you're using anyway. They care about accomplishing whatever task your application performs.
If you're really dying to try out a new framework start a new project or make a fork of an old one and update it. Learning new skills is great and fun but you don't need to update your project unless there is a real need. This is especially true if your project is non-trivial.
Learn It When You Actually Need It
Its a good idea to stay aware of new frameworks and libraries but the best way to learn is by doing. Every new piece of technology was most likely created as a solution to a problem. If you are having a problem and a new library has a solution then implement it. If not wait until you have a real use case.
Implementing a new library as a response to a real need and seeing what a difference it makes will really help cement concepts.
If You Want to Learn It Then Learn It
Let's face it sometimes you just want to learn something because it looks fun.
A few years back when ES6 wasn't even a thing there was a little language named CoffeeScript. It was billed as a more readable language that compiles to JavaScript. It was gaining some traction. Ruby on Rails (which was the it framework) shipped with it by default.
I immediately set out to learn it and started using in future projects. Well a lot of the buzz died off. Microsoft's TypeScript which was released around the same time has gained more traction and offers more long term benefits with its typing system and corporate backing.
So did I waste my time?Not at all. One of the reasons that CoffeeScript usage declined was that a lot of its most useful features were included in new releases of JavaScript. Including arrow functions, classes, default function parameters, template literals and many more I probably don't remember. So even though I stopped writing CoffeeScript years ago I was able to easily adapt to ES6. In fact I was using ES6 before it was really a thing.
So if you want to learn a new library or framework go ahead. Just don't feel pressured to learn everything.