Question

As I registered the my object as a property listener. Is it necessary for me to perform any sort of “unlistening” before I release the object.

Answer 1

You should not continue to observe objects you are not retaining (this applies to KVO, delegation, notification, any any other listener pattern). Here is the danger:

• You observe an object (“observed”) and retain it.
• Some other object also retains “observed”
• You release “observed”
• You deallocate
• “observed” changes a property and notifies you
• The program crashes

While there are several patterns that you may believe make the above impossible, they are all much more fragile than just unregistering yourself when you release the observed object, particularly in your dealloc.