cellphone battery

The battery is dead, again. What happened? A few months ago, this battery would last for days. Now it is lucky to survive during the waking hours. It was fully charged last night. Today, battery life is essential, especially with the advent of smart phones that can play music, games, text message, do homework, and occasionally operate as a phone. Many people have opted to lose the land line and go completely mobile. This is all fine, until the battery dies while standing in the middle of Times Central Station with no way to charge it.