I'd be more worried with what exactly you plan to do with said triangles.....and how many surfaces are taken into the question.
I find that it's pretty much what Gab said, use whatever amount you deem reasonable to the project without being overkill, or underkill in terms of overall visual look.
I find that it's pretty much what Gab said, use whatever amount you deem reasonable to the project without being overkill, or underkill in terms of overall visual look.