Prepare for the iPhone 5 iOS 9.1 Update
Know that if you do a little prep work, it'll go a long way towards preventing iOS 9.1 problems.
We've offered a step-by-step guide that will take you through the pre-installation process that we use before every single iOS update. You don't need to follow every single step but the more prep work you do before your install the better.
At the very least, make sure you back up your iPhone 5, especially if you're coming from something older than iOS 9.0.2.