When do you update your phone or device? I personally never update my devices unless I have to. I have an iPhone 6s Plus running iOS 9.3.3, and a Galaxy Note 4 running Android 4.4.4 KitKat. iMac running OSX 10.9.5 Mavericks, PC running Windows 7.
I used to update most of my Apple devices' OS as they came out, or shortly afterwards.
After updating my iPad Mini 2 from iOS 8 to iOS 9, I became scared to updating. It made the Mini unusable.
On my main Mac, I am still on 10.11, and I don't plan on ever updating the OS on it. But, if I did, at least I could go back to an older Mac OS. Too bad I can't do that with iOS devices.
I haven't tried iOS 11 on any of my devices due to being scare being stuck with it if I have problems.
Funny, I usually update my Android phones as soon as the updates roll out, but I tend to shy away from iOS releases. iOS often comes with new bugs, performance slowdowns, and battery issues. Although I would rush to get 10.3.