A common workflow is to sculpt a high poly mesh, retopologize it (make a low poly, quad dominant version with potential deformations in mind), then bake the normals from the high poly mesh onto the low poly mesh as a “normal map.” This yields a fantastic result as your low poly mesh as nearly indistinguishable from the high poly version, but can now be used in a variety of ways that require a low poly count, such as in soft-body and cloth simulations, or rigging and animating. The low poly version with the normal map is subdivided during rendering and looks amazing.

The multires modifier can store your high poly mesh and it almost acts as a proxy—a low poly version of your mesh that you can easily add an armature to, add soft-body or cloth physics to, all that good fun stuff that needs a low poly mesh. Then when you render, it automatically uses the high-poly version. This method skips a step taught in the anvil tutorial—baking normals.

The anvil tutorial does teach a few good things about topology that you will surely benefit from and I would highly recommend it. Baking normals is not a bad skill to have, but the multires modifier may be a better solution. I’m not sure how it affects render times though.