Classification can be taken in two ways: the simple act of dividing a subject into its main divisions, which anyone can do after memorizing a Ramean tree for the subject; or a second more comprehensive meaning which encompasses the "understanding" aspect of the subject, by defining classification not simply as a static Ramean tree, but as a process of inventing such a tree from one's own understanding of the subject.
My claim is that when taken in this second sense, classification and understanding are one and the same. If we then define logic as the art of conducting one's reason in order to attain to true knowledge (ie understanding), then classification is the same as logic.
The reason for this seems to be because classifying something requires classifying it from first principles and deducing the various divisions of the subject based on one's understanding of how the subject stems from first principles, in the same way as Euclid's elements derives geometry from Euclidean axioms and definitions. However, notice that this is the definition of understanding itself, namely, to be able to derive a subject from first principles. This is why classification and understanding are the same thing, and each implies the other: being able to classify requires understanding, and understanding implies being able to classify comprehensively (from first principles).
A practical application of this to one's own studies is that classification can be used as a kind of "barometer" for testing your understanding. The better you can classify, the better your understanding of the subject. Again, it must be emphasized that this classification should stem from one's own understanding for this barometer to work; otherwise, anyone can memorize a classification of a subject. Classification is thus a very powerful tool for measuring how well one is progressing in a subject. However, the reverse can also be applied: meditating on one's own on classifying a subject, or a small chapter of a subject, will directly lead to understanding this portion of the subject from first principles, due to the definition of classification we gave above. Thus, there is a symbiotic relationship between the two, and when both are used together we end up with a very powerful method for attaining understanding.
One can proceed simply by trying to understand, which is the non-philosophical way to learning used by most students. One could also focus instead on classification. However a mixture of the two methods seems to be best, in which case one would periodically review one's ability to classify and use this as a barometer for areas where one needs to work more on understanding. This is indeed how mindmaps function: one attempts to write out the subject from memory using mindmaps (ie Ramean trees), and where one fails is where one needs to do more work at understanding from first principles (or just understanding) - the efficient cause for classification.