How to choose your favorite old books from the collection of 7788, is there anything to pay attention to?

Confucius old book network is better and more complete than 7788. I have been collecting old books since the third grade, and it has been nearly twenty years now. My experience is as follows:

First, when buying second-hand books, we should pay attention to whether they are genuine or not. Many shops now sell copies.

Second, we must pay attention to appearance. We would rather spend more money on products with good appearance than buy products with poor quality. Don't buy books from the library. This should be paid attention to at the beginning of the collection! I didn't pay much attention to the appearance when I bought second-hand books at first, and then I changed one book with bad appearance, which was time-consuming and expensive.

Third, pay attention to the edition, especially the books of Wen Shizhe. Version is very important.

Fourth, do a good job in the book catalogue. This avoids buying too much.