This may have already been said in another answer, but I would like to answer this question my own orders.

## General Guideline ##
When you work on a team, you are not the target audience of a piece of code. Your audience is the developers of your team. Don't write code they can't understand without good reason.

 1. Unless there is a specific downside to it, all of the code should be written following a specific pattern or guideline that will allow easy maintenance by the developers who will be maintaining it. (A caveat: Following bad patterns just because they are currently in the code base is terrible practice.)
 2. If you can find a good reason to use a language specific idiom that isn't easily readable by the target audience, **add a comment.** If you find that you need to add a comment to every other line, you may want to rewrite your code to be more readable by your audience. I don't find it valuable to be idiomatic for the sake of being idiomatic.

##Specific Example##
We have a large number perl scripts in our code base. We typically only use perl for very simple operations and the vast majority of the code is written by java developers, so it's styled much like java. We have a set of perl scripts and a framework that was written by a 'perl guru' that has since left our firm. This code contains many of the more obscure perl idioms and none of our developers, including myself, can read this perl code without extended effort. We often curse him for it. :)