FBX load on Unity

Hi,

What is a good idea of two of the following:

  1. Importing FBX with all assets in it in place?

    e.g. importing even duplicate assets like trees, same buildings, vehicles, etc. all present in the fbx itself

  2. Importing only non-duplicate assets?

    e.g. Importing only single building, car, etc. and replicating it wherever required from within Unity.

Point#2 definitely saves on fbx size but does it also have +ve impact on performance?

Use option #2 since it will make sure that meshes are reused.