You are using of course LTS for your servers, right? Because otherwise it would be stupid... So, is 3 years support not enough for you?
Actually, Ubuntu LTS server is five years. http://en.wikipedia.org/wiki/Ubuntu_(operating_system) In fact, 6.06LTS server support is just wrapping up this June. Desktop versions of LTS are three years.
(1) Never draw what you can copy. (2) Never copy what you can trace. (3) Never trace what you can cut out and paste down.