When you read a long book, such as Walter Isaacson’s biography of Leonardo da Vinci [over 600 pages] or The Transformation of China [over 900 pages], it becomes simpler to read an average book of 300 pages.

When you are used to reading books of 150 pages, an average book of 300 pages will seem overwhelming.

I think it is always advisable to make it a routine to occasionally read long books, they will stretch you but will ultimately make it easier to read shorter books.