Also from the etiquettes related to caring for books, even though this topic is vast and covers many aspects, is that a student of knowledge should review and examine his books from time to time. This means that he should not amass books without reviewing what he has. So, for example, he goes out and gets this book and that book, puts them in his library and only refers to a small portion from them. One should continuously inspect all of his books.
You should go and examine what books you have so that you remember the subjects they cover. This is since some people buy the same book twice or three times or maybe even four times due to the fact that they have forgotten that they already have the book! And this is because of the few times that they inspect and review their collection.
But if one were to have a constant connection to his books – especially in countries such as ours where the libraries of some of the students of knowledge are big – if he does not review his books, perhaps he will ask to borrow the book from someone when he already has it himself! Or perhaps he may forget what is in the book or need to research a topic but because he doesn’t review his collection, he makes no reference to that book.
Another etiquette regarding books is one’s concern for donated books. Donated books refer to any book that has an imprint or seal on it that states that it is a donation (i.e. waqf). You may only keep these books in your library so long as you meet the donor’s conditions. When a person donates books he is (firstly) making them available for the students of knowledge. If you are not using the book and someone else needs it, then giving the book to someone else that needs it is better. Yes, you may have a valid need for the book, even if it is one time in the year that you refer to it. There is nothing wrong with this since this book was given as a donation for the students of knowledge.
However, if you do not refer to the book and two years or four to five years have passed by without you looking into it and you acknowledge that you have no interest in referencing this book or these books in general or perhaps you won’t need the book in the future, then in this case your keeping it contradicts its purpose.
Some scholars say that it is not permissible to keep these books (in this situation) and that they should be given to those who deserve them. They should be passed on to those who will use them and benefit from them. This is since the donor has intended them as donations for only those who will use them. If you are not using them then it is more fitting that it should go to someone who will.
There are some students of knowledge that feel that they are above keeping donated books if they have a lot of money and are able to obtain the book by buying it. This is since perhaps one may store away the book and not use it. So if the book is a charitable copy then it may be that he is sinning for withholding this book from someone who can use it. This is perhaps more noticeable in countries in which books are more scarce.