Super easy.

Mein Problem

Stock battery was not holding charge.

Meine Reparatur

I have an electronics background but I've never repaired an iPhone. This was very easy and the tool kit provided everything needed.

Mein Rat

Don't remove the screen. This step should be removed from the documentation. It isn't in the overview video and it isn't necessary at all. Fortunately I read the comments and did not remove the screen. I think that could have easily doubled the repair time and complexity.