When I was reviewing iOS memory management in the Apple documentation, I came across the section Use Local Autorelease Pool Blocks to Reduce Peak Memory Footprint
With the introduction of ARC (Automatic Reference Counting) memory management is largely taken care of for you. There are still some cases you need to worry about though, including an increase in your memory footprint caused by creating temporary objects in a loop.
Consider the following code that allows me to populate some test data into the iOS Address Book. Note that I inserted a sleep(4) after each iteration to more clearly show the memory allocation picture in steady state before a new iteration begins.