@jamii: I’ve just finished watching. This is also a phenomenal example. The concepts Lynagh uses for sizing are awesome. In our application, we have the opportunity to help the user out in many ways. I particularly like the “Humane Errors” aspect of it as well. I interpret this as: let’s not forbid the user from making a mistake (e.g. not allowing the user to input an invalid number), but let’s use the error as a teachable moment.