Andi Plantenberg from Neo writes about using lean UX on secret project where you can’t get out of the building to validate your hypothesis. There’s a paragraph I particularly like about fidelity and documentation:
Work low-fi. It’s important to acknowledge that the starting vision is wrong, wrong, wrong. It will need to change as you're building. So we work fast, low-fi and towards a common goal. We think aloud as a group, favor white-boarding to wireframes, favor hacking up screenshots rather than maintaining PSD masters. We favor the product over design artifacts and documentation. Get over it. Your product is the documentation.Unfortunately not everybody understands this reality, and we have to educate a few clients overcome their fears about the lack of documentation. Good progress is being made though, and I expect that in a few years those that understand and embrace digital will prevail over their more traditional, documentation-heavy colleagues.