It’s important to write thoroughly tested and releasable code every time…or is it?
It depends on if it makes sense. Agile isn’t a process; it’s a philosophy. If you find yourself in a situation where you aren’t sure if you’re hitting the mark or not, it’s not a sensible use of resources to document and completely test your code if the point is just to mock up a prototype to show a customer. You don’t want to ship the product, just demonstrate concepts. Does it really make sense that you should devote the resources to something that’s little more than a scratchpad for the user to view?
Don’t get carried away with following a prescribed Agile process. If you’re new at this, follow the rules (don’t hide behind them) and don’t build half-baked software. If you’ve been doing this for awhile there’s nothing wrong with bending the rules if it makes sense to do so.
I love to lose a good argument. I’m sure there are opinions to the contrary.