Why have people looked the same for the last 20 years?
dazeddigital.com
dazeddigital.com
Look for changes in fashionable colors, in types of fabrics, in shoe styles, in hair styles, even in phone styles and colors, etc, etc.
Remember the matching 'His 'n' Hers parachute-fabric tracksuit outfits? Or the bright-colored hair? Or cargo-pants? Or wrist-watches? Or trainer-shoe styles, colors and fabrics? Or the amount of denim? Or checked fabrics? Or spotted fabrics? Or hat styles?
A good way to discover the changes is to look at films or music videos made over the years, and look for what stands out as 'different from today'.
Get your eye in, and you can pick when a film was made to within a year or two.
It shouldn't take much poking about on RuNet to find some comrades in beehives and floral dresses, comrades in sideburns and huge lapels, and comrades with teased hair and legwarmers.
(that said, the picture starting the article could have been taken in 1993 or 1983 as well, and maybe even in 1973. The kids would not have been fashionable for those decades, but they wouldn't have stood out as being anachronistic either.)
then again, "prep/sloane ranger/bcbg" is still going, with minor adjustments, for what, at least a century now? eg https://www.youtube.com/watch?v=i6XsIL0jIBI
Or how Mad Men popularized midcentury suiting around 2009?
Or That J Crew Gingham Shirt?
Or how the bare midriff came back out of nowhere with a vengeance the past couple summers?