What models are going to be used are usually determined during the pre-production phase of a project. Based on storyboards, you will know their positions in the scene and distance to the camera.
Determine which objects never get close to the camera and which ones either are (for static images) or do (for animated objects).
- If an object is far from the camera at all times, decrease the default settings.
- If the object is middle distance away from the camera, leave the default settings.
- If the object gets close to the camera at some point during the scene, increase the tessellation settings a little more, but only enough to achieve an acceptable level of smoothness.