What happens if you have upgraded and then decide that the new version isnt what its made out to be and decide take the old version off & re-install the old version and use that.You would then be using a previous version that shouldve been destroyed.
It's a good thing you're not dealing with wives there Hypo..
Best thing to do is just do the subscription thing. I know for vanilla Autocad, the subscription is $420srp but, if you just decide to renew it every year, it'll cost you $595srp. Now, some think "I'll just skip this year and upgrade next year." well, guess what, you're STILL going to pay for this years upgrade.. at the upgrade rate at that..
Moral of the story: Just get subscription, it's the way everything AutoDesk is going.... You WILL be assimilated, resistance it futile.