I guess that, before to join a engine instead of another, one must know what it may handle. I didn’t saw any good tutes around about modeling for unity, and specially about polycount; nor any exhaustive guidelines on approximative polycount, nor it is easy to find any specific Q/A in this forum or in the unity forum (too many posts, mostly with unrelated questions and answers). So, the question is (and hope that someday someone will put an exhaurient answer in the official guide):
when projecting a character for pc (obviously for a 3d person game; a 1st person got visible only hands and weapons), what is the min and max polycount for it, independently from the surrounding geometry, attached items (weapons and so on) and client’s system?
Min 1, Max whatever your memory/GPU can handle. Aside from the fact that polycount has almost no meaning without context (what shader, how many textures, how big are the textures etc.), asking for a min and max polycount of a single object within a scene and completely ignoring hardware, surroundings and everything else does not make ANY sense whatsoever at all. And all that aside: if you have to worry about the poly count of your models for a 3rd person PC game, your models have too many polys.
I’ve built a few games for mid range, lower end machines in mind. I usually build my characters with about 4k tris. This is lower than most games today, but my goal was to allow a wider range of machines. I keep my textures below 1024 for this. With that in mind, you can get acceptable quality (UT2004 was built close to these specs). As for current gen games, you can double this. But from my experience, You’d really need to optimize your game in order to run this smoothly. You can build a model.