My readers will know that I’m a big Harry Potter fan. I have read all the books, including the “text books”; seen, and own, all the movies; and been a member of Pottermore (now Wizarding World) since its inception. I love the entire Wizarding universe JK Rowling made up out of whole cloth (with some borrowing from other authors of terms and names). Her imagination is remarkable, and she rarely, if ever, drops an anachronism.
But I noticed some anomalies; conditions which perhaps don’t really exist in a world of Witches and Wizards, as Rowling portrays it. I also pay attention. For instance, there is mention of Gamp’s Law of Elemental Transfiguration, which says that there are certain substances that cannot be conjured up out of thin air. The two most important are food, and money.
A wizard can double the amount of stew in his pot, if the kids invite their buddy to dinner at the last minute. But he cannot conjure up stew if the pot is empty. Ron Weasley, when talking about the law, says that you can increase the amount of something you already have. So, I wonder why, if given a Knut, any wizard could not create more Knuts. If he has a coin in his pocket, a wizard should be able to make more coins. Which, theoretically, should mitigate against any wizard being poor.
In the Harry Potter books, Rowling mentions fairly often how poor the Weasleys are, with all their children and Arthur working at the Ministry in an out-of-the-way office with little prestige. 
Ron eats home-made sandwiches on the Hogwarts Express, and his mother has to buy him second-hand dress robes. And he grows quickly out of his ordinary school robes. Why should this be? Molly Weasley is as good a witch as any, so shouldn’t she be able to simply conjure up some new robes for Ron?
In the summer before their second year at Hogwarts, the Weasleys win a 100-Galleon prize, and use it to visit Egypt, and their son, Bill, who works as a curse-breaker for Gringott’s, the Wizards Bank. Why couldn’t Arthur multiply that 100 Galleons to 500? And he could always keep a Galleon or two around, to use like sourdough starter, to make more. Then his family wouldn’t be poor.
Then, there’s the case of Remus Lupin, introduced in the third book.
He is a werewolf, having been bitten in childhood by Fenrir Greyback. Now, when he is introduced, on the Hogwarts Express, he is described as tired, and threadbare; carrying a very worn suitcase, tied up with twine. We can understand the fatigue-just being himself is tiring for someone who can’t find work due to his condition. [Editor’s note: David Thewlis, who played Lupin in the films, was my favorite-he was perfectly cast, in my opinion]. If he is a wizard, shouldn’t he have been able to renew his suitcase to be brand new, so he wouldn’t have to tie it with twine? And couldn’t he have repaired his clothing, so they were not threadbare?
Let me advance a theory. Rowling made the Weasleys and Lupin poor, and sometimes threadbare, to make a point. She wanted to show how relative poverty affected the characters, and the wizards and Muggles around them. She wanted to show how being poor didn’t make a witch or wizard bitter or angry; at least not her characters! She showed how the Weasleys were a very happy family, and made the best of what they had. And, once Harry gave Fred and George his Triwizard Tournament winnings, she showed how they made a wonderful living with their joke shop.
Lastly, there is Severus Snape, the nasty Potions Master at Hogwarts, who made Harry’s life difficult the entire time he was at school.
Only in the Half-Blood Prince book did Rowling give a hint of what Snape was like at school. She reveals that he had always been an oily sort of character, and had a reputation for not washing himself or his clothing much. I have always wondered why that was. Snape was as good a Wizard as anyone, so why didn’t he just clean his person or clothing, so as not to give Potter and Sirius more reasons to sneer at him? Also, the bathroom facilities at Hogwarts were pretty good, so if he wanted to, Snape could have kept himself clean. But he didn’t. And I think Rowling ensured that he didn’t…just so the teasing he got from others could be a lesson.
Yes, these are minor quibbles, but it seemed to me to make the Wizarding World not quite accurate, if the powers of Witches and Wizards were as specified. Next, I want Rowling to write “A History of Magic”. I think that would be a wonderful book to read, don’t you?
Calling-all-RushBabes 
I would consider that there might be some sort of moral or class code that looks down on using wizarding powers to improve one’s circumstances visibly or frivolously. We in America don’t have classes, other than self-imposed. We don’t have inhibitions about trying to better ourselves in ways visible or even ostentatious. We forget that in most places in the world, life is very class conscious and restricting on those in lower stratems.
I wonder if it might be like counterfeiting. It’s not real money, after all; it’s a copy of the original. Remember the leprechaun gold they encountered in book four? It disappeared after an hour or so. What if the replication spell wears off at some point – or the copy wears out more quickly than the original? Replicating coins stops being a ticket to a better life, turning into a ticket to trouble instead.
Likewise with the clothing. All clothing wears out, sooner or later. Use too much magic on it, and it might fade or become threadbare faster. Replicating clothes when the spell eventually fades away means a witch or wizard might end up slowly becoming naked in the middle of the school day. Not fun.
As for the stew, that won’t have to last as long as clothing or coins. And we don’t know if someone who eats replicated stew doesn’t eventually need a midnight snack. I imagine a replication spell works for a few hours at most, then fades away; that makes it good for food in a pinch but not for things that need to be more durable – i.e. clothes and money.
Interesting theory! Too bad there’s no way to test it out. If I ever meet JK Rowling in person, perhaps I’ll ask her.
My nephews, and particularly my now-school-librarian niece, loved Rowling’s world. I know that they also enjoyed Gaiman growing up. Are there others in addition to Rowling whose work you enjoy, RB?
Yes. Jack Whyte wrote the “Camulod Chronicles” relating to King Arthur. The first book of the series is The Skystone. He starts with Arthur’s grandparents as Roman Britons, and carries the story through past his death. Every book is a treasure, and they should be read in order. All the history is accurate, peopled with real characters. He has a whole section about the Pelagian Controversy. Even you would like them, Nanda.