In an iPad application we recently developed, we had several UICollectionViews loading many images that could be resized. Like the camera roll in the system app, we had a Grid layout with hundreds of image thumbnails that could go fullscreen if tapped.
During QA, we had performance issues: the memory footprint increased every time we entered in a UICollectionView and we loaded the images grid with hundred of images. The increase was a steady 21MB every time we entered and no memory was being release at any time.
At iOS’s whim, the application received a Memory warning and, unable to deal with the memory pressure, it crashed.
Always trying to avoid premature optimisation, now was indeed the time to sharpen our performance skills!