Manage Your Battery Life
With the tools that iOS 9 gives you, you should get into the habit of monitoring your device's battery life.
The iOS 9 update's battery usage tool comes with some new features that help make it easier to track your usage and the amount of battery your apps are sucking up. You can now spot the apps that are killing your battery in specific situations. This will allow you to adjust accordingly.
Battery life issues could emerge at any time too. And while it's easy to blame Apple, there's a good chance that the drain is being caused by your bad habits or youe apps. That's why you'll want to monitor them.