What “look” would be the hardest to associate with a particular era? This will probably be easier to figure out for a male than a woman, since women’s fashions seem to be more dynamic.
Suits for men haven’t changed all that much, though I guess different materials have been used, and different widths of ties and lapels, but overall, they don’t seem to have changed too much.
Eye glasses and hair seem to be easy give-aways as well. For some reason people in the 80’s had really BIG eye glasses (what was the deal with that?), and in the 50’s (?) you could get an idea on the quality of a person’s sight by looking at the thickness of the lenses (“Coke bottles”). Hair seems to change a lot too.
If I wanted to go with a look that, when seen in a picture 10, 20, 30+ years from now, it would be hard to determine what decade the picture was taken what would that look be? Are there any styles that have withstood the test of time?