We all know that. We are not arguing with that. We all understand that code is always written to solve a problem or make something more efficient, or create a new functionality. In that way it is most of the time an asset. That is a given. What we are talking about is a higher-level view which you get from a lot of experience in big codebases and big projects, in which code is almost always also a liability. It means that when you write a piece of code, the wise thing to do is to always assume that it will be a liability (in addition to all the wonderful things it does) to someone, in some situation, in some time. That way one can easier think through all the ways this liability can show itself, and thus somewhat mitigate those ways. Returning to original topic, choose a stable mature language/system which a lot of programmers know, instead of a new shiny one (even though the shiny one might be 5% more efficient in lins of code or something) - is a great way to reduce the liability surface in the future.