Use it, or you lose it
How we learn has, for long, been a significant interest for humans. Already the ancient cultures understood that systematic training creates a better result, and the Romans coined the proverb “Repetition is the mother of learning.”
More than a hundred years ago, when Hermann Ebbinghaus discovered the Learning and Forgetting Curves, it became clear why it is necessary to continuously repeat when you want to acquire a lasting skill. Without repetition, knowledge will vanish.