Quick answer
Set backup frequency from the maximum data you can afford to lose; set retention from how far back you may need to recover.
Define RPO and RTO
Recovery point objective is how much recent data you can lose; recovery time objective is how long the site can remain unavailable.
Use off-site storage
A backup stored only on the same server can disappear with the server. Keep recovery data outside the failure domain.
Test restores
Periodically restore to staging or a disposable environment so the first restore attempt is not during an incident.
Where Cloudways enters the decision
Cloudways Flexible includes configurable off-site backups and on-demand backup controls. Those features are useful when paired with a written restore process and independent copies of irreplaceable business data.