> ...isn't that pretty much what "make clean" generally does? Yes, exactly. The point is that "make clean" is used because the Makefile does not capture the d

> ...isn't that pretty much what "make clean" generally does? Yes, exactly. The point is that "make clean" is used because the Makefile does not capture the dependencies perfectly. So, "make clean" ensures a clean rebuilt. But that can cost a lot of time, especially in large projects or when using C++ header libraries such as boost::python or Eigen. Now, if you were sure that your depedency description is correct, you could skip "make clean". And this is what redo provides, because, at the one hand, it allows to use dependency information provided by the compiler, and moreover, it covers a lot of corner cases precisely. The corner cases not always working is why "make clean" is typically used for.