The real target for code reuse, the way I see it, is reuse of code between projects. That is where the big gains would be by not having to start from “scratch” in each project. And that is what’s difficult to get right.

I see variations of the following statement quite often

“One the things we memorized (and later spilled onto our exam papers) is that OO enables this really good, absolutely awesome thing called ‘code reuse’.”

This is a common misconception, that OO is about re-use, and that inheritance enables re-use. The core of OO is dynamic binding, and how through dynamic binding reuse can be achieved (http://www.parashift.com/c++-faq-lite/big-picture.html#faq-6.9). Inheritance is a way of facilitating dynamic binding, not a way of re-using code (eg: Google ‘composition over inheritance’, Bloch’s ‘effective java’ also makes this point)