When blueprints and when C++ should be used?

Development Programming & Scripting Blueprint
1

Hi!

First of all, I think this question is for UE4-devs: do you have any ceratin rules about when you should use Blueprints and when you should use C++ code?

Where should we seek for the balance between these two ways of creation?
For example: we have “ticks” in Blueprints and in code. Which one have best performance?

2

watch this: Hourences.com – The Solus Project

He explains lots of things, and there are bits about how to split BP and C++ programming in project.
I think this is best into to making some real projects as indie in unreal engine.