I remember this XP seminar I went to ages ago...

Halfway this guy makes a neat statement about software re-use: (paraphrased from memory)

I spent my pre XP professional OO life, chasing the idle hope of writing something re-usable... The chase always led me to writing the overly generic component that would try to serve the universe... my tendency for 'genericity' always led to pulling in possible future aspects that never were needed all together in any project... so the component always got rejected as reuse candidate mainly because it was too big for anyone's use (bringing the other developers into contact with concerns they didn't even want to think about)So now I'm writing stuf that gets the job done: no more re-useable focus, but just plain usable stuff.... Guess what? People are re-using those in their projects.

I had a flash of the same kind while explaining the basics of plugability to the Luxembourg crowd...

Software reuse is not about the one component that is going to be used in each and every project in the world (it is only partially). There is more re-use a lot closer to you, outside of that one component you work on: Re-use, odly enough, is achieved through the component that can be thrown away and replaced easily because you had it correctly hidden behind some interfaces. At the moment you throw away that one component, all the other ones in your project are... reused?

Reuse is not the cause, not the goal; try to enjoy it as a nice bonus from a job well done :-)