Pros and cons of not creating another variable called Shout?

I'm not sure if it's a mistype when you were posting the question or not, but the way the instructor code is writen should alert(shout); not alert(stringToShout);, just throwing that out there because it made me chuckle a bit. Anyway, going back to your question.. there's a slight performance difference between reassigning (what you do) and creating (what the instructor..supposedly?..does). I wont get into all the technicalities, as for something like this, it's almost negligible. It is worth noting, however, that usually the difference between reassignment and creation boils down to how often a variable is used in a program and what kinds of things you're doing with it. If it's being accessed on a regular basis (i.e. every page load, anytime something on the page updates, anytime data is sent or processed, etc.) then it's better to cache it as a variable and call it good. In a case like this, you're probably good with throwing it away by using your method and just overwriting the variable via reassignment every time, but if you were to do a bunch of stuff with shout (the processed string) or you needed to retain the original stringToShout it's better to store it as a new variable.