I found that when I double-tap home button to bring up the springboard, then hold and kill my app, applicationWillTerminate: is not triggered.
This leaves me puzzled as to where I should place my termination procedures.
I looked at this post: How to know whether app is terminated by user or iOS (after 10min background) which says otherwise.
I'm running iOS 6.1.3 on a 5th-gen iPod.