Here are some things you can do to limit your data usage:
- Always turn off Cellular Data when you don't need to use it.
- Don't do things that use a lot of data, e.g. streaming video. Find a Wi-Fi network for that sort of thing. And to be sure that you are using Wi-Fi, turn off Cellular Data on your mobile device.
- Close apps when you're not using them. Many apps will run in the background, which means that they could still be using data.
- Watch out for apps that use pushed content and notifications, e.g. email, Instagram, Facebook, Twitter, weather updates, sports scores. If possible, set these to manual updates.
- Limit the use of Siri: he/she uses a lot of data.
- Cut down on your use of email or web browsing.
- Set your email to view only. That way, you won't be downloading full attachments.
- Turn off cloud-syncing apps, such as iCloud and Dropbox.
- Turn off automatic downloads.
- Don't update your apps using cellular data.
- Use a data-monitoring app to get some idea of how much data you're using.
If you're using an iPhone or iPad (Cellular model), the Apple support site has an article describing how you can view and adjust your data settings and usage:
https://support.apple.com/en-us/HT201299
If you're using a mobile hotspot, there are some additional things to bear in mind:
- Your device will be connected to the hotspot using Wi-Fi and will behave accordingly, so any settings that limit data usage over cellular connectivity will be ignored. Pay particular attention to the points listed above to limit your usage.
- Turn off all automatic downloads, including software and browser updates.