It's not uncommon for my phone to shut down after it's hit 8% remaining battery. Or I'll be watching a video with 45% left, and the next second it'll cut me down to 25%. There have been a few instances where I've gone from ~25% to completely empty in a flash, leaving me with a dead phone much earlier than I'd anticipated. So now I really can't leave my place for more than maybe 4/5 hours without my charger.