Wi-Fi Assist is a new feature in iOS 9 on the iPhone that potentially could improve internet access for apps and services. However, it comes at a cost and it could, in fact, cost you real money. Is it worth it?

What is Wi-Fi Assist?

A mobile phone can access the internet in two different ways. One is by using a wireless network and the other is by using the mobile phone network, in other words, mobile data. There is no limit to the amount of data you can download and upload on a Wi-Fi connection, which makes them great for things like viewing photos online, streaming music and videos. It is all-you-can-eat data.

The same is usually not true of mobile data. There is a limit to the amount of data you can use and this depends on the terms of the contract you have signed up to with your phone service provider. It may be 500MB, 1, 2, or even 4GB.

Having two different ways that an internet connection can be established is useful and when there is no Wi-Fi hotspot in range, you can still send and receive email by using the mobile data connection.

You have to be careful how much data is being used, because if you go over the limit set out in the contract, then extra fees can be applied and it can be expensive. When there is a Wi-Fi network you can connect to, then the phone can send and receive as much data as it likes.

Wi-Fi Assist is a feature that chooses the best way to connect to the internet, but it is regardless of the data used. If the Wi-Fi signal is poor then mobile data is used because it will provide a better connection. This can be useful in situations where the signal varies or if you are walking around and the phone automatically switches from Wi-Fi to mobile seamlessly and without the hassle of having to manually switch over.

There is a potential problem with it, and when the Wi-Fi is poor and it switches to mobile data, you could end up using quite a lot. In fact, you could go over your limit and this could incur additional charges on your phone bill.

This will affect people with a low limit more than those with a high limit. The question is, is the convenience of a better connection worth the risk of going over your data limit?

Turn off Wi-Fi Assist

If you plan to leave Wi-Fi Assist in its switched on default setting, you should keep an eye on the amount of mobile data the phone is using. If it uses a lot, you should switch off Wi-Fi Assist. In fact, to play safe, you should keep it off all the time. Then it will not cause you to use more data than your allowance.

Go to Settings and tap Mobile Data (on some phones, perhaps US models, it is called Cellular). Scroll down to the bottom of the screen where you will find the Wi-Fi Assist switch. Turn it off.

It is a feature to experiment with and to be aware of the dangers of using too much data.