Well, I don't really know if you guys have already discussed this topic but I've been wondering about this question for a long time and maybe there's someone here that can help me understand it better. Here's my question: why is Apple making their phones thinner and thinner instead of adding more battery to improve the phone battery life? I mean, thinner is great, but isn't Apple taking it too far? The current iPhone 4S is really thin, why make it even thinner? it is technologically viable to add a second battery in order to "double" the battery life? I know nothing about engineering so maybe this isn't possible to achieve. This can also be applied to other Apple devices. For instance, the new iPad it's almost all battery. Why didn't Apple did the same with the previous iPads in order to improve battery life? Hope someone here can explain me technically why this is/isn't possible, even if from an economic point of view this doesn't make sense to Apple.