Question on Collider Resource Consumption

Hello everyone, I was wondering (in general terms) about how many/much resources are consumed when checking colliders of different vertice counts (essentially mesh colliders for objects that don't suite primitives). For example: are resources consumed linearly (every vertex adds equal resource consumption)? Is it multiplicative? Is there a minimal resource charge under a certain vertex number? Any insight beyond "Try to use primitives" is appreciated.

The practical application of this for me, is that when I go back into all of the meshes I need to figure out if I should "Just split the meshes where they naturally occur" or "Split every mesh multiple times regardless of anything" - to make sure they perform well but not waste time splitting meshes (and uv mapping and texturing them) if they don't really need it.