>The assertion has been made that typical applications have between 40%-50% of their code actually run during testing.
>
>I am curious to see what percentage of code you test (actually run during development/unit test/system testing) for:
>
>1) The development of a system from scratch.

100% - More testing time = Less support time

>2) The development of a new/replacement system but using code parts (including classes, functions, etc.) from existing and well-running systems.

100% - See #1

>3) Developing revisions to an existing application.

110% - It's way too easy to break somebody elses code

HTH,