Comment by alwillis

> It seems clear to me that they use OS updates as a way to eventually slow your device down

This sounds like an exaggeration of what happens after an upgrade: iOS has to re-index your entire phone for Spotlight, etc. Same thing for Photos if there have been changes.

Depending on which phone and the amount of storage, your phone can feel kind of sluggish for a while until the background indexing is done.

If you update before you go to sleep, your device will be fine in the morning.