Believability is a big part of making a great looking render. And just as we discussed in Photorealism Explained, materials are a huge part of whether or not the final render looks realistic or not!
This goes beyond just photorealism too. It applies equally to stylized cartoony stuff.
Disney actually developed a Physically Based Shading workflow for Wreck it Ralph, to make the world feel more believable:
So physically based materials are important for every artist.
The best part though? You only need to do this tutorial once. Then you can just save it into your default blender file, and have beautiful materials forever :)
This tutorial is mostly material theory. But I also demonstrate how to assemble your own node group can be used to make realistic materials like this:
Links from the video:
Make something cool using this PBR material? Post it in the comments below!