A few months back I thought I was going to write a blog post about how to look for RID Pool depletion in environments. Then I got side tracked with something (probably finding out why Mad Men isn't on yet) and Ned Pyle wrote an awesome post that would of put anything I would have wrote to shame anyways.
If you haven't read it I recommend you stop what you are doing and read it! So now you see how important that is to manage. There is a new KB Hotfix I recommended highly reading through it and then going through the proper testing channels for your environment.
MS KB 2618669
Some key highlights directly from the KB
Cause:
In certain rare circumstances, a domain controller may issue recurring requests for RIDs from the global RID pool every 30 seconds. If repetitive requests for RID pool updates are unchecked for a significant time, the global RID pool may experience too much consumption, and in extreme cases, may experience complete exhaustion of the global RID pool.
Resolution:
To prevent too much consumption of the global RID pool, we recommend that you take the following actions:
Happy testing!
Mark "No Diving In the Shallow End Of The RID Pool" Morowczynski