Best Practice: Migrating transports to Prod (system down etc.)

Hi all

This is more of a process and governance question as opposed to a ChaRM question.

We use ChaRM to migrate transports to Production systems. For example, we have a Minor BAU Release (every 2 weeks), a Minor Initiative Release (every 4 weeks) and a Major Release (every 3 months).

We realise that some of the major releases may require SAP to be taken offline. But what is SAP Best practice for ANY release into Production? i.e. for our Minor BAU Release we never shut down any Production systems, never stop batch jobs, never lock users etc.

What does SAP recommend when migrating transports to Prod?

Thanks

Shaun