Disclaimer: maybe this thought is a bit different from the previous post because this is an old article that I post again on hasnode.
Bottom-up, learning this way is indeed very tiring, but we really know a lot, our knowledge is broad, even to things that we may not need or we never use at all.
Top-down, this is in line with the concept of 'learn if you need it', or the cool term “Learning how (and how not) to learn”, or art that is not important. This model is usually a relaxed person. in the world of coding, for example, this type is only focused on being able to generate real profits.
Perhaps the most important thing is to understand when these two methods are used. back to the example of the IT world, lectures are learning bottom-up methods, we learn from scratch. But when it's practical in the world of work, you have to be able to learn top-down.
In the IT world, learning to react, vuejs is not necessarily profitable. I've learned both of these things, but in fact my office is full of Laravel.
The interesting thing about the top-down method, we are limited to the things we are dealing with. for example, when we first encountered reactjs, we met the term component, there we just googled and understood its definition.
Lately the two methods above have somewhat affected the way I study. now i rarely study, for now i focus on domain/tech which i really use in my work, laravel. does not mean reducing quality, it is more focused on one domain we will really master that domain.
Conclusion: our time is not all for learning, especially on things that we don't necessarily need.