By the hairdo. It s her neck. An old one doesn t have one, at least from the back. Young women have necks that go all the way around.
Old women have necks only from the side and they re usually in multiples.
These women are selling a product aimed at the senior among us and they are usually seven feet tall, with no protruding stomachs, perky breasts, slim, but grey haired. Smooth, taut, from the top of those breasts all the way to the chin. They say you can tell the generation of a woman by her hands. Necks can be tightened, of course, leading to age obfuscation. But the woman cares, greatly so.