"ARC is awesome, but I highly suggest that you don’t use it until you can manage memory yourself. In other words, don’t rely on ARC until you understand what it’s doing."

This is not good advice.

ARC is meant to free the programmer from having to think about memory management and allow us to instead think about what we're trying to express in our object graphs and algorithms. Deciding where to call retain and release is an old, tired dance and is where the vast majority of memory leaks and app crashes come from. With ARC, we can just relax and let the compiler insert all those pesky retains and releases where it knows they should go.

There is no reason for newcomers to learn the old style. If a newcomer is reading old-style code, she can skip over the retain/release calls and pretend they're not even there, because they don't affect the algorithm.