cocoa touch - When best to remove an observer from a property when using a UICollectionViewCell? -

In my UICollectionViewCell subclass, I set the model and then using the KVO model on a Inspect the property. I am not sure now when the best place to remove the supervisor is.

When the model changes, then I can remove it, but this means that when the screen is removed from the screen, the supervisor will still be active and put it in the reuse queue. Similarly -prepareForReuse

-viewWillMoveToSuperview: ?

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It does not know how I did not see it earlier, but its The answer is -collectionView: didEndDisplayingCell: forItemAtIndexPath: at UICollectionViewDelegate.