That is the million dollar question now isn’t it? Not only for AutoCAD 2009, but every time a new release comes out, especially when they are yearly. The times a new release came out after two years of waiting it was easier to jump into it (for some reason).
It is my professional opinion that no release has ever been a “must upgrade.” I don’t feel that there is an absolute reason to upgrade every release; even if you or your company is on the subscription plan.
I do feel, however, that it is in the best interest of a company to upgrade every other release. My suggestion to everyone that asks this question is to get on the subscription plan and upgrade at least every other year. Go ahead, make the argument, why pay for something and not use it? Because it is cheaper to buy a release and pay for the subscription every year than it is to buy the release every other year. Plus, if you upgrade every other year then you are essentially keeping up with AutoCAD. You will never be more than one release behind, which in my opinion is acceptable.
To answer the question at hand, I honestly can’t say (in my opinion) that upgrading from AutoCAD 2008 to AutoCAD 2009 is a must. But I can say that if you are running AutoCAD 2007 or later, then it is a good idea. There are enough features between two releases that justify an upgrade.
Another idea is to look at the DWG file types as a release, and the others as an update or patch. The latest are the 2004 and 2007 types. The 2004 type is covered in releases 2004, 2005, and 2006. The 2007 types are 2007, 2008, and 2009. I assume that release 2010 will be a new DWG type. Instead of upgrading every release or every other release, perhaps every third release is an option. Up grade at the last release of every type, that way you have all of the options available for that DWG type. This would be a good reason to upgrade to 2009 and then essentially wait until 2012 to upgrade again. You will start to get a little behind, but I feel that it is still acceptable. And, if you are on subscription, it is still cheaper to buy it every year than to pay the full price every three years. Beyond three releases it isn’t cheaper.
This might not answer the question at hand, but I feel that it is really a much deeper and more involved question than simply upgrading to AutoCAD 2009 or not. Until Autodesk provides a release with a feature, or feature set, that will absolutely enable you to make more money, then there will never be a reason to upgrade to a single release. You and your company have to look at “the big picture.” The bottom line is that you need AutoCAD to either produce design drawings (as a service) or to produce drawings that enable you to create something to sell. Can you do that with your current software? Will the new release improve production efficiency more than it will cost? That last question is the killer.
Consider all of these concepts and come up with a plan that suits the needs of your company and its budget. Then you will be able to answer the question, do I upgrade or not?