Before Xcode 5, Auto Layout was probably the most annoying feature you could decide to implement in your app. Flagging "Use Auto Layout" was as scary as jumping into a lion's cage, and people tended to use it with a sort of reverential fear, originating from stories told by fellow developers.

Luckily, it has improved immensely, and now, it's a completely different story: working with Auto Layout is extremely simple, and Xcode fully supports all of its features.

I would go as far as to say that Auto Layout now classifies as mandatory knowledge if you're serious about building modern user interfaces. New additions to iOS 9, such as UIStackView, and the growing lists of screens sizes are probably just what you need to leave all the doubts behind and start using it right away.