PKS namespace

Hi,

We are in the process of implementing the PKS infrastructure. Since we are quite new to this topic, would like to get some guidelines/best practices on the below point.

Since we are going to use the same setup for the Development, QA & Production , what  is the best practices to segregate these environments.

Is it have separate clusters   for each environment [DEV/QA &POD]?, and create namespaces within to segregate different projects?

Or

Have one or two clusters [one for DEV & QA and one for PRD] and segregate each project with respect to the  namespaces?

or

Any other recommendations?

Kindly advice.

Regards,

Sam