[keyle]

I don't know, this doesn't make much sense to me. Usually you go from a set of specifications provided by a business analyst and then presuming you have a style guide and a 'widget library', the UX designer then 'formally' implements a prototype which can then be tested asap, tweaked ad-nauseam.

Once that's done, there goes your formal specification. We know what we're doing, how we're going to do it and we can work on the impl.

[kumaraman]

I assume the "set of specifications" is normally provided via some sort of project tracking software like Jira. A problem with this is these specifications get lost in history, not to mention become outdated as the features evolve.

From my experience having well a documented code base allows you to understand decisions at a later date, especially when key members have left the company.

[lazyasciiart]

Or the company switches to a new tracking tool and loses all the old data in the move.