Program protection is connected to hardware. If you do not agree to this fact in any way, do not pay. However, by changing your equipment, you can get the new key for free ( the previous key will be blocked).
When you buy program you get from 6 to 18 month of free updates (depends on a license you choose). And then you can renew your license for updates. To prolong the validity of the license for one more year, please see "License manager"
Additional license gives you an option to use program on your second PC. It has one restriction – automatic updates are unavailable. The owner of additional license has to update the prior license first, and only then copy update file to second PC. You can order an additional license in the "License manager".
Some license packs include programming of custom extensions for Zebroid that you need. They work under extensions API and can’t exceed the capability of API.