As I have posted in another thread; with mild gaming, a lot of web surfing, and some video clips here and there while re installing everything from new, The longest usage time I got was 10 hours and 25 minutes. I have it using auto brightness which on my new mini 4, instantly changes brightness up or down at the slightest environmental ambient light change. Also using touch fingerprint to unlock. All other settings and apps replicate my mini 2 and Air 1. Same exact usage on my mini 2 just recently got me 13 hours and 20 minutes of usage before auto shutdown. It is on IOS 8.4.1, no touch finger print, and auto brightness is gradual not instant and will change brightness only up if environmental ambient light is brighter. If it darkens in the room the mini 2 stays where the brightness is at unless you put device to sleep then wake it back up. Anyhow, what are other mini 4 users getting in usage times and please be honest so we can compare if its hardware issue or an IOS9 issue using different builds of IOS9? Thanks!