External Models in Quads or Tris

Do external models (from like Maya or Max) have to be in quads or tris, and if Unity accepts both, which is better?

Also, what’s usually a good poly count for a human character?

Unity will automatically triangulate any polygon that comes in - including ngons (5+ vert faces), however ngons might come across weird and as a general practice for artists they should be avoided. It is my personal preference to do quad modeling with as few tris as possible, but both quads and tris are acceptable.

A good polycount for a character depends on a multitude of factors, such as platform and genre. For a good example of multiple platforms’ characters I suggest Ben Mathis’s portfolio. (Also - best name for a website evaaaar)