Recognizing where usable light exists in any scene is a necessary skill if you want to excel at photographing people.
Instead of dragging out a lot of lighting equipment, the more experienced photographers learn early on to assess where the ‘good usable light‘ is and try to work with it.
By goodusable light I mean light which you can use either to fill, highlight or accent your subject as opposed to the visible light which enables you to see or locate your lost contact lens.
The trouble is, that particular skill only comes after you begin playing with lighting your subjects using flash or strobes.