The iPhone battery goes down quickly. Particularly, if you use your phone a whole lot, you may find yourself feeling hopeless if the unit dies right when you need it. Be in the practice of keeping it connected to an electric outlet whenever you can; this may help to make sure the battery is charged up throughout the day. If you are traveling get an iphone 5 car charger to keep it charged as you move from place to place.
If you are working in one app and want to return to an application you were previously using, benefit from app switcher.