My two cents is that this process ends up varying between clients and their release cycles or development philosophy. It's tough to give a guideline other than the features that have been built into Tealium.
I think the most useful feature is Publish Targets available in the Advanced Settings of the Tag Configuration. The tag can be restricted or allowed based on an environment. That way, for example, if you are waiting on something to be released while it is going through testing you can switch "Publish to Prod" to "No". Any extension scoped to the tag will inherit the Publish Target settings.
I'm not sure if anyone else will have insight but hopefully this helps spark a conversation.