Hi Mike
You don't really need to backup the CC Essentials in particular, but it is always wise to keep a backup of all your Template and Custom Content folders in case of any problems.
By default the location of these folders for CC3 are shown below. For CC2 just change the number 3 to a 2.
C:\Users\Public\Documents\Reallusion\Template\Character Creator 3 Template
C:\Users\Public\Documents\Reallusion\Custom\Character Creator 3 Custom