I was having a conversation with a gentleman on Friday night at a business mixer and discovered that he was an IT infrastructure consultant advising a fairly large size enterprise on a new structure to support their very distributed user-base.
During the conversation he mentioned his surprise at the amount of money it was going to cost his client to implement Microsoft Office 2007 for their 7500 users. We talked a little more as I wanted to understand what program the company was considering purchasing through - and I found out that they had formerly had Software Assurance but it had expired almost 2 years ago. What this consultant didn't know (and neither did his client and no one else was bothering to point it out) is that Office 2007 was released to the general public on 1/27/2007 and (don't quote me on this date) was available to their volume licensing customers around October 2006. Software Assurance entitles you to the latest version of the software released as of your expiration date - whether you've installed it or not. That is in perpetuity (for traditional licensing).
The result being, that was $2m the client was going to spend for software they were already licensed for! I told the consultant to go back to the client and have them review their licensing statement of the Microsoft Volume Licensing web site to make sure dates were good but that it looked like that was money they could keep in the bank (and to hire us in to review the rest of their licensing plans to avoid any other costly mistakes).
This is an area where we frequently find clients uninformed or misinformed. Talk to an unbiased licensing professional before making a software investment - what you don't know can cost you a lot of money!