Oreo cookies, grilled cheese, and jelly donuts. What do these things have in common besides tasting great? They all have stuff in the middle. You may have some designs where you need geometry between 2 faces. SOLIDWORKS has a feature that you might not know about. It’s the Mid Surface feature. What it does is create a surface between 2 faces. The surface will move if the two faces move. It is located under Insert>Surface>Mid Surface.
With the surface in the middle, you can thicken it and make it a solid.
This helps build in some “Design Intent” and intelligence into your model.