I have now worked on two scientific code bases that are written in C++. One is for classical physics, the other one does quantum field theory. But that is not the point. The point is that there is a lot of code and there are lots of scientist working on that code.
Version control is a neat thing when programming, but I sometimes forget which project uses which system. All of my projects use git, some others use SVN, Mercurial or Bazaar. When I work on the command line, I would like to know whether the current directory is version controlled and which system is used.