In order for the line out audio to work for an iPhone 5 or 5s dock, make sure you have iOS 7. I had iOS 6 running on the iPhone 5 and the line out audio would not work.

iPhone dock connector problems, with and without accessories
Aside from the traditional maintenance of oil changes, and keeping fluid levels correct - what else will help prolong the engine's life?

I recall a few years back gasoline additives were the thing to go with - what's the best/recommended one currently? If any.

Edit: I recall reading about each gasoline brand having their own set of additives at one point, where it was suggested to cycle between a few different brands every X amount of km/miles. The reason behind switching was so that the next brand would cleanup any sediments left by the previous brand. How likely is this in today's world? And better yet, how important is it?
