Speaking of smart pieces, here's one by Matt Panzarino at The Next Web on the iPhone's battery:
Do you know why Apple doesn't do 'full on' multitasking? Why it is so incredibly strict about how apps suspend themselves in the background and exactly what location services they use and for how long? Do you know why they reject apps that waste CPU cycles? Why lightning fast push and pull email is still smoke and mirrors for the most part?
I'll save you the conjecture. It's the battery. The battery in the iPhone is so wretched, in fact, that millions of dollars were spent developing incredibly low-power LTE chips in order to make it feasible to include the faster wireless technology in the iPhone 5 at all.
I still use my iPhone 4S, and I stress out like crazy over conserving its battery. Exacerbating the problem is the fact that I have to keep my screen brightness on full blast in order to comfortably see. To help with my battery worries, I bought a Mophie Powerstation Duo that I keep in my bag with me, along with an extra 30-pin cable. This way, I can charge my phone while on the go so as to not worry about losing juice. I've used it quite a bit, and it's great. I highly recommend it.