It is our policy that if you purchase a product and a major release comes out within 30 days, you get the new version for free. We do not have a set release schedule for Camtasia Studio, so I am not sure when the next major version will be released. However, we are in active development.
Furthermore, you can get a sense of our past release cycle here: http://www.techsmith.com/camtasia/his...
We also support previous versions of the software as well, so we won't leave you high and dry no matter what you decide.
I should mention that upgrades receive a discount and we have a maintenance plan. This isn't really my specialty, but you can learn more here: https://store.techsmith.com/maintenan... or, I can help you get in touch with Customer Service.
One last thing--Have you tried CS 7? You can run the trial along side CS 6 so you don't have to uninstall your current version. You should give it a shot if you haven't. The change and new capability between these versions is very dramatic and you can see full details in the first link I shared.