First you should have saved each tax return as both a PDF and a .tax file after you file every year. Then if you still have the program installed on your computer or you saved the installation file then you really don't need the CD at all. If you do keep any of the CDs the you only need the current year plus the 3 open years but you don't ever need more than 5 since those tax years are no longer supported.
ALWAYS …..
Backup
your return as
BOTH a PDF &
a .TAXFILE:
https://ttlc.intuit.com/questions/1912403-how-do-i-back-up-my-tax-file-in-the-turbotax-cd-download-s...
And PASSWORD PROTECT
them AND
copy/save them to a removable medium:
https://ttlc.intuit.com/questions/2565836-how-can-i-protect-the-tax-files-on-my-computer
https://ttlc.intuit.com/questions/1914893-how-do-i-password-protect-my-tax-file-in-the-turbotax-for-...
