Well as an example, on a Sprint HTC phone the crapware auto-started itself not only when the phone powered on, but apparently several times a day (despite using an app-killer). This wasn't just 1 or 2 apps, it was like 10. So my idle battery was draining away in part because I couldn't stop this phone from running things I never intended to use. I have never been happier since switching to the iPhone from that broken ecosystem.