Is there some kind of log on my iphone that tells me exactly when I've been using the phone?
It seems like you're trying to review your iPhone usage and we can help.
There are two Settings menus on iPhone that can give you insights into how and when you're using your iPhone.
Check out these articles that can help you with Screen Time reports and battery usage:
Use Screen Time on your iPhone, iPad, or iPod touch
About the battery usage on your iPhone, iPad, and iPod touch
Let us know if that helps.
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