So often, when I have written code with a view to being able to handle possible future expansions or changes in requirements, the life I have saved has been my own.
I am fortunate in two ways though:
1. I have a boss who says "Get X done by time T" and leaves me to it
2. There is actually enough time to do X by time T with a bit of slack which I can use to make things happen better than they did last time around.
When you build a house, and someone comes along and demands an extra room, it is *so* nice not to have to rebuild the house first!