Back in the early days of Apple’s media players—more specifically the iPod—choosing which capacity to buy was easy: if you had enough stuff to fill the smaller one, get the biggest one, and if not, perhaps the smaller one would do. In fact, that advice worked pretty well all the way up to the fifth-generation iPod, which added video—and therefore some very large new files—to the mix. Now, with everything from books, magazines,…
