Updating AutoCAD and Revit can be difficult for a few reasons. If you are not on subscription, there can be tension between the users and the purchasers of the software – when do we outlay $$$ to do the upgrade?
In that situation, there is often lengthy discussion related to the cost vs benefits of any particular upgrade.
After that discussion is resolved, the next question is – can our current hardware run this new software?
The following comic from Architexts draws on these themes…
http://architexts.us/2011/01/14/updating-autocad/