Hi,

The clone frequency is also tied to the release cycle frequency/deployment frequency which is followed for a particular account/project. 

For example- let's say you have a major release comprising of deployments for a new application/existing application once in a month and then you have bi-weekly maintenance or minor releases comprising of bugs, minor enhancements, product fixes, known errors etc., in this case its best to clone your sub-prod Instances from the Prod Instance post the completion of each major Release in a month. This will make sure that even your maintenance/minor release work gets cloned over to your sub-prod Instance as the major Release is usually done during the last week of a month, where as minor Release will take place during the 2nd week or so. 

In addition to this, its always advisable to have your Dev. work being carried out in the Dev/Sandbox Instances in update sets containers and then once the cloning gets completed, those update sets can be imported back on the sub-prod Instances. Or, the concept of having different environments for Dev. work can also work, if in case your account has the flexibility to procure more Dev./Sandbox Instances from your ServiceNow Alliance/Relationship manager and these Instances can be used only for Dev. work for major Releases, these can be kept as separate from the Instance on which maintenance/minor release work is done.

Regards,

Mishu

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