[collyw]

A lot of the time (certainly in my work) the requirements are incomplete / vague enough, that it is easier just to build a prototype and work from there. As such tests will just require two or three times as much code, and there is a fair likely hood that they will be thrown way afterwards.

I know this does not fit waterfall or TTD / agile methodology, but I am certain that there is a very large percentage of IT workers that have to work this way.