In youth we learn, in age we understand

आचार्यात् पादमादत्ते
पादं शिष्यः स्वमेधया ।
पादं सब्रह्मचारिभ्यः
पादं कालक्रमेण च ॥

A student acquires a fourth of his knowledge from his teacher, another fourth from his own intelligence, the third quarter from his fellow students, and the rest of his knowledge through experience in due course of time.

In youth we learn, in age we understand.