No, once your serial number has been authorized to your iLok account, it is yours and there’s never a need to authorize again. If installing to a second or third computer, just activate the license to the computer using License Manager after UVI and the library are installed. You can install the library on as many computers as you want, and the activation is managed with the License Manager app. Deactivate your license in License Manager from your computer if you want to reinstall the OS, sell the computer, or change the hard drive or logic board.