Well you can only use it to reinstall Turbo Tax for 3 years. And now since you have to log into an Intuit Account when you first install it, all your downloads and licenses are listed there (even if you bought it from somewhere else) so if you need to install it again or install on another computer, even on the other operating system (Windows, Mac) you can download it again.
Only the program is on the CD. So you should be saving your returns as both pdf files and the data files ending in .tax2023, .tax2024 etc. And save backups of them off your computer, like on a flash drive or external backup.