How memory techniques work
Our memory is not equally well suited to all tasks. Some things are surprisingly easy to remember (like where our bed was in our childhood bedroom), others are quite difficult, like a random sequence of numbers. The art of memory is about figuring out how to use the strongest aspects of memory for everything, rather than about how to make our memory as a whole stronger. A physical analogy might be learning to lift things with our legs, rather than working on making our arms stronger.