Skeletal Mesh vs Static Mesh

I would like to start out with I am still new to Unreal Engine. I know a bit but still have a lot to learn.

I am currently playing with a weapon systems. I know the difference between static mesh and a skeletal mesh. My question is, is there a performance difference between the two? Also when adding attachments to a skeletal mesh, does that mesh need to be skeletal or can it be a static? I have my skeletal mesh and have the sockets ready to dynamically add the attachments just not sure if either or makes a difference?

Static meshes, depending on mobility, will render much faster.

Overview of mobility:

Actor Mobility | Unreal Engine Documentation

General performance guidelines:

  • only use skeletal if you need keyframe animations
  • make all static meshes the lowest mobility required

General attachment guidelines:

  • you can attach static to skeletal, and vice versa, but …
  • static meshes only attach to static mesh of equal or lower mobility
  • only attach “movable” static meshes to skeletal meshes