No-one likes big phone bills, but it is easy to exceed the allocation on your contract unless you keep an eye on the data you are using. If you have an iPhone, use these techniques to reduce data usage.

Avoid apps that use data

Social networking apps like Facebook, Twitter, LinkedIn and others, all try to keep you up to date with the latest posts and messages and they do this by frequently connecting to the internet to fetch the latest updates. Email apps check for new messages, WhatsApp, Snapchat and others, connect to the internet to check for status updates, and there are many more apps that constantly update.

This behaviour does not matter if you have a Wi-Fi connection because there is no limit to the amount of data you can transfer. When you don’t have a Wi-Fi connection the phone transmits and receives data over the mobile network and this is limited and expensive if you use too much.

It would be useful if you could avoid apps that use mobile data, but it can be hard to give up social apps like Facebook, Instagram and others. Reducing the number of apps on your phone usually results in less data used though, so get rid of any you do not need.

Check the data usage

The first thing to do is to keep an eye on the amount of data you have been using recently. Go to Settings > Mobile Data (or Settings > Cellular).

Look down the screen to the MOBILE DATA section and see what it says next to Current Period. It shows the amount of data used. Is it near to the limit specified in your contract? 1GB, 2GB and 4GB data limits are common and you will probably be on one of those.

• Turn off Mobile Data if you are close to your data limit
• Turn off the switches for apps that do not need mobile data. They will update only when Wi-Fi is available. Do you need Facebook to update on mobile data? No. Do you want to use FaceTime on mobile data? It would use a lot and it is safer to turn it off. Check the other apps.

What is the current billing period?

The iPhone tracks data usage and calls and it shows this information since the feature was last reset. Scroll right down to the bottom of the Mobile Data (or Cellular) screen and there is a Reset Statistics link. It is best to press this on the day your next billing cycle starts so it is in sync with your bill and you can tell when you might be about to use too much data, calls or texts.

Of course, you may forget to reset the statistics on the right day, so go to the Calendar app and put a recurring event or reminder on that day to press the Reset Statistics link.

• Turn off Wi-Fi Assist: It uses mobile data when the internet is slow and turning it off reduces data usage. The internet might not be as fast, but you save data.
• Turn off iCloud Drive: When the switch it on, iCloud uses mobile data. Turn it off to only use Wi-Fi connections for transferring documents and data.
• Reset Statistics: Press this on the day your new billing period starts.

Your phone service provider tracks your usage and it may have an app that shows how many minutes call time, texts, and data left for the current billing period. It should show when the billing period ends and the next one starts. See the example above. Your carrier's app will look different, but it probably has the same information.

Don’t fetch email images

Go to Settings > Mail and there is an option to stop the app using mobile data completely. Turning it off will obviously reduce the data usage, but then you would only receive emails when connected to Wi-Fi. You might want to leave this switch on. However, scroll down to the MESSAGES section and there is an option to Load Remote Images. Turn it off to reduce the data when reading emails.

Turn off roaming

If the phone cannot get a signal from your own carrier, it might use another carrier’s network and when data is used, it can incur extra charges. This most commonly happens when travelling in another country and it is something to watch out for.

To avoid using data and being charged when travelling, go to Settings > Mobile Data (or Settings > Cellular) and press Mobile Data Options. Turn off Data Roaming. Your carrier may allow some data roaming though, so check your contract.

Stop background app refreshing

Some apps refresh in the background and they can use mobile data even when you are not actually using them. Stop them by going to Settings > General > Background App Refresh > Background App Refresh and set it to Wi-Fi.

It is a global switch that applies to everything, but if you really need to save data, set it to Wi-Fi.