Smartphones are powerful and versatile tools, but they can be dangerously addictive too: we've all know the sinking feeling when we realise we've been looking at Twitter for an hour and it's long past time to be asleep. The problem can be far more serious when kids are involved, and many parents would love to be able to impose more effective controls on their offspring's use of iPads and iPhones, or on their usage of specific apps.

Both groups will be pleased to hear that iOS 12, the current version of Apple's mobile operating system, features a range of tools for monitoring and limiting device usage on a per-app basis. In this article we explain how to use the powerful Screen Time features.

Monitoring app usage

Screen Time covers a range of features, but these can be divided into two main categories: monitoring and limiting.

Every week you will receive a report detailing how much you've used your iPhone or iPad over the past seven days. In the popup summary you'll see a daily average usage time (and whether this is up or down on the previous week, and by how much), the average time between pickups, the average daily number of notifications.

How to set app limits with Screen Time for iPhone & iPad: Summary report

Screen Time divides each day's usage into a bar chart colour-coded for social media, entertainment and other categories, and showing the most-used apps. And there's a section called Insights that offer observations that it feels will be useful.

You can tap through from the summary to see more details. You'll be shown graphs of daily usage, the length of your longest session, and the amount you've used your device after bedtime, which is likely to be particularly problematic. And the per-app information gets more detailed too, listing which ones are causing the most pickups and sending the most notifications.

How to set app limits with Screen Time for iPhone & iPad: Weekly activity summary

All of this is valuable information for analysing ways in which your device usage is becoming unhealthy - and the specific apps and types of use that need to be limited - but also giving you targets for improvement.

If you want to see analysis of your app usage at any other time, open the Settings app and tap Screen Time. At the top of the next screen you'll see how long your devices have been active today, and a small graph showing (in broad category terms) how that time has been divided - social networks, entertainment and so on.

Tap anywhere on this top section and you'll be taken to a more detailed report page. On this page you can choose whether to view collected data for all your devices , or just for a device of your choice (tap Devices at the top right). This choice will be remembered if you go back to the summary page. You can also switch between one- and seven-day reports, which won't be remembered.

How to use Screen Time to limit iPhone app usage: Report

Limiting your own app usage

If an app on your report list has an orange sand-timer icon next to it, it means you've set a limit on that app's usage. (Limited apps also appear in a separate category, labelled Limits.)

Tapping through to an individual app within Screen Time allows you to set a limit, customised by hours and minutes and potentially applied to specific days only. Under Limits at the bottom of the app or website's report page, you'll see the option to Add Limit.

How to use Screen Time to limit iPhone & iPad app usage: App Limit

The limit doesn't only apply on this device, note - it will also apply on any other devices signed into the same iCloud account.

Screen Time will pop up a notification when you've got five minutes left of your daily usage limit.

How to set app limits with Screen Time for iPhone & iPad: Time limit

Limiting your kids' app usage

If you've got Family Sharing set up, Screen Time will know to send a weekly activity summary to your kids, but to also send a summary of your kids' activity to you, so you can keep an eye on what they've been up to.

You can create what Apple calls Allowances for your children's app usage, and this is more sophisticated than iOS parental controls in the past. And it's all set up from your parental device.

How to set app limits with Screen Time for iPhone & iPad: App limits for kids

You can schedule Downtime, when the child must be away from their screen. Among the Downtime options, you'll see options to set a start and end time, and to block device access at the scheduled Bedtime.

How to set app limits with Screen Time for iPhone & iPad: Downtime

Like the app limits discussed earlier, Downtime sends a notification when five minutes is left, and allows users to ask for more time. (You'll get the chance to say yes or no.)

You can also set time limits for individual apps, and limits on types of app (such as games, social networking and health & fitness) or content (by age rating, for example).

Finally, you can specify apps that should always be allowed, such as the Phone app or educational apps.

More in-depth advice for parents can be found in our article How to set up parental controls on iPad & iPhone.