There was a time in my life, when my parents didn't have enough money. We used to get one uniform and one shoes per year. We used to borrow used textbooks from friends in upper class by exchanging it with their siblings in lower class.
It was in 7th class when one day while having a math test, Sir Zaheer asked us to use reference formula from the back of the book. I failed as reference page for formulae was missing from my book.
That day Sir Zaheer said: "Son! Never get 'used textbooks'. I understand it costs money but it is not a good habit for 3 reasons. First, it may be outdated. Second, it may have missing pages but lastly and most importantly, it may take away your psychological craving of conquering new book as old textbooks do not carry the charm, smell and curiosity of hidden treasure".
I never believed that - but now I do. As someone told me once: "Fortunate is the man who holds a virgin woman, built his own house and smells pages of a new book".