Accidentally was passing by this relatively old article Lean UX: Getting Out Of The Deliverables Business (March, 2011). I find it worth reading anyway, as well as, and even more, the comments to it.
It provoked some thoughts about the process. The very essence of the lean/agile approach is to reduce the time, amount of documents, and costs, according to this article. But my personal impression (and as far as I can judge an impression of some commenters) is that reducing time of conception development we, instead, are increasing time of endless iterations in the quest for the same very conception.
That is, “agile” is a great tool for those who don’t actually know what is the product they are developing right now. When we don’t have proper and comprehensible conception, we are forced to search it, and for this search “agile” approach is really a solution.