Poly flow , triangles and 5 edge verts

So I gathered up enough courage to ask all of you great welders of verts, a question thats been on my mind for a bit. When modeling while watching your edge flow and trying to keep the polygon(triangle) count down, is it better to have; a triangle, a five sided polygon, or a vert with more than 4 edges going into it, are verts with 3 eges better than verts with 4 edges, and where to avoid 5 edge verts?!?. Because the minimum polygon count is going up should you just keep everything in 4's by looping your edes ,connecting them defining your shape that way , or should you loop edges where it is important to underline broad shapes and when you do that do you still try and keep everything in 4's or can you use 3 sided,5 sided polys, and verts with more than 4 edges going ito them, and if so where is the best place to use them.

Any enlightenment you can impart on me will be greatly appreciated, i will try and provide examples of what im talking about once i get my internet at home

Thank you