The fourteen-day return policy for iPhones is pretty standard with carriers, so if you normally get your phones from them, then you’re in no danger of getting confused. For those who buy their iPhones from Apple Retail Stores (and online as well), though, you will want to know that you now only have fourteen days – in case you have problems.
It used to be that the return policy gave customers thirty days leeway, but Apple’s web site now shows the revised, shortened return period.
Now I can’t think of any reason to return an iPhone unless it’s inherently damaged, but just in case you are going to buy a new unit any time soon (although you might want to wait for the iPhone 6), make sure you remember the revision in the Apple return policy.