A solid and entertaining treatment with good C++ examples:

Coupling and Cohesion

by Paul Watt

From the middle of the article:

... To further clarify this statement, not all code should be reused.

Why Not?

Because the majority of software that is written is designed to fulfill a very specific purpose. The challenge is to find the balance point between generic reusable building blocks, and a tool or application that meets a need. Generic software components are very valuable, however, they are almost useless by themselves...

And gems like this:

... For every statement of code that you write or use, you should ask the question: Does this add value or risk?