I've been using one of these for the past 6 months (they were going for ~$70 on eBay when I got mine). I don't use the "Life Mode" feature, and the battery doesn't even come close to lasting all day. When using the phone with screen on you can watch the battery percentage tick down ~1% a minute, and listening to streaming music over Bluetooth with screen off give you about 3 hours of life total. In practice I find myself leaving the phone plugged in, disconnecting it only to change location or leave the house. On excursions a battery pack is an absolute must-have.