While you may UPGRADE with a CD, you are never current (as soon as first UPDATE or REVISION is released you are behind, missing out on any releases that address bugs in the software)

And at least a one-time connection to the internet would be required in order to activate your program. We used to get something like just 10-20 time of starting QB before it would no longer let us log in without going online to activate.  So maybe it is now 180 days, and if you never activate your license (entering it during install alone won't do it as that one-time connection for verification is mandatory)

Even when you turn OFF automatic updates (and since you never connect to the internet it is impossible to update) you may get said 180 reminder to check for updates. Close the popup window and move on.  

One thing you are missing and nobody mentioned yet, no matter how much you paid for your CD, you DO NOT OWN the software on that CD. QB is a "borrowed" product. You are buying not the software but the right to use it per the EULA.  The software remains the property of Intuit, forever.