Requirements management is needed. New development projects come with specifications, regulatory requirements, statements of work, etc. Keeping track of whether each part, assembly and finished unit comply with what paragraph of what requirement of what contract is time consuming at best with Excel.
The new custom objects in 2013 along with projects in 2012 might lay the groundwork for this.
No I have not tried 2013 yet. I am currently installing 2011 and expect to be able to upgrade to 2013 by the end of the year. I had thought I could do something with the custom objects but hadn't thoroughly thought through it. Yes, UDPs may also help. I wasn't prepared to build my own solution right away if Autodesk had something in the works and had more manpower to throw at it.