Noob UE4 Persona question

Hito

So I get how UE4 handles humanoid skeletons and animation retarget. But the retargetting "duplicates" the animation assets for each character they are being retargetted to... doesn't this unnecessarily increase the # of duplicate assets in the project? What happens when animations get changed? Retarget them all over again?

Ispheria

There's a thing just for Unreal 4 questions in the technical talk section 
http://polycount.com/categories/unreal-engine