Licensing is a hard and absolutely vendor-specific problem. Not only that, many vendors, especially the larger ones like Microsoft, have multiple types of licensing regimes that change things based on:
- How large you are
- What industry you're in (non-profits, education, government, large corporation, small corporation, and SOHO are all discrete licensing categories with their own quirks)
- How much licensing you purchase
- What kind of contract you buy
- Where you are located or where the licenses will be deployed
Especially for the larger companies like Microsoft, licensing is its own career-track and one that more and more often is not found in the SysAdmin office. It is found in either your Purchasing office, your value-added-reseller's office, or the LargeCorp's sales office.
In our company we have one person who specializes in purchasing IT license-bearing software. She handles Microsoft and Adobe licensing, as well as a host of other complex entities like ESRI, MatLab, Apple, Novell, and AutoCAD. It is her entire job to know these things and we've made significant savings because she can focus her whole effort into figuring the fiddly bits out. It has saved us a lot of money. She is neither Server person or Desktop person. When license-servers need setting up I do that, but she provides the license keys that goes into them and all of the legal mucking about that does into obtaining them in the first place.
She's a licensing person, and is mostly the kind of person who can answer these questions. I'm not, neither are people like me. But even she would be hard pressed to answer questions for a 30 person small business, since she spends her entire day enmeshed in a large, public (and therefore governmental) higher-ed organization that has completely different licensing options.