IMO it’s bad to reinvent the wheel every time you need a new face, good point about needing to keep practising but there are other ways to do that.
Humans are genetically similar to 99.97 percent or something like that. Yes the lines in the face look different, but we all have the same underlying topology, the potential for those lines. It’s like lines in the hands of our palms, all slightly different but basically very similar - for instance you’ll never see someone with the lines going in the opposite direction, from the thumb to the pinkie.
This is my fourth generation topology. I’ve spent a lot of research time on it, it’s a big improvement on the last version; it seems to work very well so far.
Here’s the male version:

(And yes, for an extremely fat person I would have to go back to the drawing board.)
I’ve marked in red some important areas - the wrinkles at the corner of the eyes are very hard to get right if the topology is wrong. The big nasolabial fold is tricky because on some people it connects a little higher on the chin in the smile, but I think I got a good average placement here, I think you got that pretty close too Luny. The little wrinkle at the corner of the mouth is sometimes overlooked. In many old people it does seem to cross the nasolabial fold like that.
The bridge of the nose actually displays this surface shape in some people, and I believe we all have the same structure there, just many of us (like most asians, and me) don’t show it.
(The top of the nostril is one of those areas I might decide to change later, most people have a line there, and modeling it diagonally across a quad is a big pain.)
About triangles and 5-sided polys - in Maya what you see here works very well, never tried it in any other app.