Usage history

iOS keeps its own record of what ran on the device and what it used. Usage history reads that record, which is why it can answer questions about last Tuesday that no live capture could.

What is in it

Per app, per session:

• Start and end time
• Duration
• Which hardware it kept busy — CPU, GPU, display, radios, location, sensors
• Energy attributed to it

Coverage reaches back up to six months, depending on how much the device has retained. Older entries thin out; recent weeks are dense.

What it is good for

Answering an overnight drain. Nobody was holding the phone at 3 a.m., so there is no capture to look at. The history shows what woke, when, and for how long.

Finding a background offender. An app that runs for four seconds every fifteen minutes never appears in a live capture, and adds up to a lot over a day.

Confirming a fix shipped. Compare the two weeks either side of a release for the same app on the same device.

Establishing a baseline. Before optimising anything, know what normal looks like for this device and this user.

Reading it without fooling yourself

• Duration is not cost. A media app open for two hours may cost less than a location-hungry app awake for twenty minutes.
• Attribution is per process. Work an app triggers in a system service is attributed to that service.
• The user’s day is a variable. A heavy day and a light day for the same app is usually the user, not the code. Compare like with like.
• The record belongs to the device. Resetting or restoring the device clears it.

Practical procedure

1. Connect the device the complaint came from — not a similar one.
2. Open Usage history and set the window to cover the period being complained about.
3. Sort by energy, then look at what is above your app as well as your app itself. Half of these investigations end with the answer being a different app entirely.
4. For your own app, open the sessions around the reported time and read which hardware was in use.
5. Export the window and attach it.

Privacy note

This is a record of how a person used their phone. If the device belongs to a tester or a customer, say what you are reading and why, take only the window you need, and delete the export when the ticket closes. See also the user agreement on authorized use.

Free tier limits

Usage history and the data-analysis views are paid features. See pricing.

Next steps

Energy and battery · Performance monitoring · App management