That you can still get your stuff done in R13 implies that you don't have to rely on imported drawings or models from elsewhere. Or, everyone else you work with is long accustomed to "saving down" for your use (and maybe shaking their heads about it).

I just looked: R13 isn't even an option in "Save As". For some unfathomable reason, 12 and 14 are.

Anyway... in my experience in what a lot of universities are now calling "architectural engineering", the architects buy AutoDesk's latest bill of goods first. Soon, all of their consultants are expected to upgrade. For the first 15 or so years of the cycle, that almost always meant a hardware upgrade to run the new software.

It's happening again... with "Revit". We had an intro training class here in the office last month. I'm not holding my breath, though: the MEP packages are way behind the Archi's. When a new box lands on my desk capable of running Revit, then I'll know we're getting it.