[codalan]

UML was (and still is) really useful when embarking on a greenfield design. Most people I've worked with know some basic UML notation, so when it comes to whiteboarding and refining the design, it makes sense to go with that.

In terms of artifacts for future maintainers? Maybe not as helpful. As previous posters have mentioned, the diagrams go stale very quickly if the engineering department isn't disciplined about keeping documentation up to date. But this is true for any documentation.

Some diagrams (class and activity, in particular) are less valuable as time passes. I can get the idea of the class structure by just looking at the code itself. The class diagram just ends up being a stale representation of the code.

It is unfortunate that UML has developed a reputation as being overly complex. Now I see more ad-hoc diagrams being created, with whatever notation/symbols make sense to author, rather than using a common diagram system that can be read by many.