Periodic backup of the NSX Advanced Load Balancer configuration database is recommended. This database defines all clouds, all virtual services, all users, and so on.
Any user capable of logging into the admin tenant is authorized to perform a backup of the entire configuration, that is, of all tenants. A restore operation spans all the same entities but can only be performed by the administrator(s) capable of logging into one of the Controllers using SSH or SCP.
It is a best practice to store backups in a safe external location in the unlikely event that a disaster destroys the entire NSX Advanced Load Balancer Controller (or cluster), with no possibility of remediation. A recommended backup schedule could be daily or even hourly, based on how often the configuration changes.