If you don't back up very frequently, you're always vulnerable to having something recent taken.
If you do back up very frequently, you need to make some hard choices:
You need to connect to your backup media very frequently. But, you don't want any ransomware that may find you to also find your backup media; that would defeat the purpose of the backups.
Backing up a lot of data very frequently will end up requiring a lot of storage. If you erase old backups to save on storage, you're vulnerable to your latest backup turning out to contain only ransomware-encrypted data.
If you don't back up very frequently, you're always vulnerable to having something recent taken.
If you do back up very frequently, you need to make some hard choices:
You need to connect to your backup media very frequently. But, you don't want any ransomware that may find you to also find your backup media; that would defeat the purpose of the backups.
Backing up a lot of data very frequently will end up requiring a lot of storage. If you erase old backups to save on storage, you're vulnerable to your latest backup turning out to contain only ransomware-encrypted data.