> Code should be self readable, and if you get
  > to the point where it isn’t, then you may have
  > to rewrite few bits. This is not always
  > possible though, especially for temporary
  > hotfixes or hacks. In this case, comments are
  > a must.

* Sometimes business decisions may not make logical sense, but someone says "do it this way." It makes sense to comment this in the code.

* The code might tell you what it's doing, but not necessarily why it's doing it.

* You may be making use of legacy components that you are unable to rewrite. It may make sense to comment on their use within newer code that interfaces with them, making it possible for people to bugfix the interface without needing to delve all the way into the legacy component.