I think the ideal number for a book about real life is 200 pages length. This will not make the other person lazy to finish the book, unless your story is really interesting. You need to make them interested on the first page. You need to let them know what they are about to read. You need to let them know what is the purpose of sharing what you need to share. You need people be busy in knowing everything about the book. If that is what they will see your book, for sure regardless of the pages they will finish it and even give a great reviews about it. Although, it takes a lot of money publishing more than 200 pages length of books, I think it is worth a reading even the long one when you keep your readers interested. I love long thick books.