14 DAY TRIAL // Most mobile phone users don't have an unlimited data plan, and this is why the Wi-Fi network at home is their Internet connection of choice.
However, if you have a router that can't cover all the rooms in your house or has signal problems, after you've updated your iOS device to iOS 9, you might have also received a huge bill at the end of month.
The culprit is the newly added Wi-Fi Assist feature in iOS 9 which, unfortunately for iOS device owners without unlimited data plans, will automatically switch your iPhone or iPad to the cellular connection when the Wi-Fi signal was poor.
Having an automated system taking care of switching between Wi-Fi networks and your cellular network wouldn't be a problem if you would have enabled the feature on your own.
Disabling the Wi-Fi Assist feature will allow you to save big on your phone bill
Regrettably, Apple has decided to take matters into its hands and have all its customers connected at all times, at any cost, by automatically enabling the Wi-Fi Assist feature on all iOS devices updated to iOS 9.
If you think this is a bad idea, you're right, but there's still something you can do to avoid paying extra on your monthly phone bill besides sending the check to 1 Infinite Loop, Cupertino, California.
You can disable the Wi-Fi Assist feature by going into Settings on your iOS device, in the Cellular menu and turning off the Wi-Fi Assist feature at the bottom.
Another solution would be to leave Wi-Fi Assist on and only turn on the cellular data connection for the app you need to have connected to the Internet at all times.
This can also be done from Settings > Cellular, by toggling on the button next to the app you need to keep connected at all costs.