To get a better understanding of what a wallet backup is, please read: What is a wallet backup?
Fortunately, you do not need to make backups each time you receive or send a transaction with your wallet. All you need is to initially create a wallet backup and store it safely. Your whole wallet, including all future transactions, can be recovered from this initial wallet backup.
By default the BitBox02 automatically creates a wallet backup on a microSD card during setup.
Optionally you can also display your wallet backup in the form of 24 recovery words and write them down.