How to configure node variations? I have a content type with a lot of different fields. Now this content can have (but not always) variations, which have the same fields, but different content.

I don't know how it would be best to organize this on the admin side. I could use child nodes, but if I have children, I'll have an empty parent. Basically what I need is to have multiple sets of the same fields for a content item.

I don't know if this is understandable, you might think of the as product variations or subproducts, here's an example:


Macbook (this only has title + description)
 -- Macbook Air (title + one set of characteristics)
 -- Macbook Pro (title + 2nd set of characteristics)
Mac Mini (title, description, characteristics)
iMac (title, description, characteristics)
As @W.M. said, i will use Conditional Fields module Conditional Fields along with Field Collection Module.

Essentially you will first define collections of fields (this is a kind of grouping of fields that are related. ie retina screen details), and then you can make this fields collections to appear if another field value is set using Field Collection.