>>533369>poles, which are just as bad as having tris.
Poles look a bit nicer, and at least for organic modeling, are considered more desirable than tris.
It's also just good practice to learn how to redirect topology with poles and form proper loops.
Sidenote: Is it possible to form good loops with tris? I'm unsure because I've always just used poles.
It's the same general concept, however. You'll be placing them wherever the mesh isn't deforming a whole lot.
For faces, there are 3-4 popular places to put them.
1. The upper inner corner of the eye
2. The cheekbone
3. The side of the head
I suck big dick at body topology, but I'm assuming the loops just follow muscle/skeletal structure (Shoulder blades, pectoral muscles, etc).
For static models, it does not matter.