Different people have different balance of skills. I like to use highschool chemistry as the litmus test. On the extremes there are people like me, stereotyped as successful physicists or engineers that love the math side but hated memorizing the tables of ions (poor ability to memorize, good ability to reason), and the people that are stereotyped as successful biologists that hated the math in their chemistry courses but memorized the entire periodic table just by looking at it (tremendous ability to memorize, poor ability to reason). Of course there are also all the people in-between. If you lean towards memorization, obviously if you need an answer, your best bet is to remember when someone told you the answer. If you lean towards reasoning, your best bet is to conceptualize a few fundamentals, and derive the answer on the spot (because you have no hope of recalling it.) This difference means that some people are naturally suited for some fields of study over others, for example the usefulness of recall in biology where everything is a huge tangled web of interacting parts. Another example of these stereotypes in action is the meme that engineers can't spell (which makes sense in the English language, because spelling has little in the way of overarching structure and is mostly recall).
The point of all this being, you have to recognize where you stand on the reasoning-recalling spectrum and adjust your learning strategy accordingly. Something that works for someone on one end might not work at all for someone on the other.