Just as an experiment, I wanted to test the theory of fully discharging the iPhone 5 battery to increase capacity. On its very first full discharge cycle, the phone went 1.8 days with 19% battery remaining (usage time was 7.7 hours), which extrapolates to 2.2 days for a full cycle. I then let the phone go completely to zero (auto-shutoff), and recharged all the way to 100%. Coming back down again, it logged 1.375 days with 32% battery remaining (usage time 6.0 hours), extrapolating to 2.0 days. This is slightly less than the pre-full cycle trial, though the diffference is probably within experimental error. So, according to this very unscientific study, I was not able to support the theory that the lithium battery inside an iPhone 5 is benefitted by fully discharging to zero. Comments welcome.