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The outers are pretty robust, more so than the inners. I have not seen or heard of a problem with the outers breaking. Then again, if broken while slamming down on a rock, chances are the person replaces the tie rod and heads to the alignment shop.
As Hummer H3 says, if you are going on an extreme off-road trip, take an extra one with you. Very easy to replace, and the alignment can wait till you get to civilization.