For the most part, those who had more interaction with the public, or clients, went by one set of standards; those who worked behind the scenes had another. Bankers and lawyers naturally had a slower go. In 1998, a banking exec told The New York Times that even though dress-down days “are a hot item” and “it’s been brought up time and time again,” his bank was “high-profile” and required workers to wear business attire. In 2000, what was then Chase Manhattan Bank took its Park Avenue office business casual, but only last year did JPMorgan (which by then had merged with Chase) change its dress code. Corporate image and employees’ desires helped define who went casual and when.

Another dimension of the way cultural change unfolds: There is always a point when “We don’t do that” slides into “Yeah, we do that.” “Casual Friday” became a palatable, kind-of-fun way to introduce new standards into the office. By 1996, nearly 75 percent of American businesses had a dress-down day—a figure up from 37 percent just four years earlier. Casual Fridays allowed both managers and employees to “collectively select” what constituted casual dress for their specific environment. Still, HR managers struggled to contain casual to just Friday or to provide guidance for an office that was proactively “going casual.” Business casual proved hard to define. In 2000, one uncertain office worker told researchers from the University of Pennsylvania’s Wharton School, “Now it’s what kind of slacks, what kind of shirt, what’s acceptable and what’s not. The ranges and limits are tested, and they are a lot more ambiguous.”

Still figuring out how to market the mix-and-match nature of the garments—quite different from selling a suit—retailers struggled to meet consumers’ needs. “I don’t think department stores are good at explaining the why of it,” a consulting firm executive told a reporter for Women’s Wear Daily’s eight-page insert in September 1995 called “Casual Evolution.” Rather than showing buyers “how to put the outfit together for the kind of business they are in,” department stores stood by outdated floor plans that separated pants from shirts and shoes. Companies such as The Gap or The Limited that were in charge of both their manufacturing and their retail provided shoppers with an achievable and versatile look.

Confusion among consumers died off in the early 2000s, but for managers, one question loomed: Does casual dress make workers less productive? A chorus of academics came up with an answer: not sure! Some managers argued it empowered workers to bring individuality to the workplace, which in turn inspired creative thinking. Other managers considered casual dress a distraction that too often devolved into sloppy habits.

Thirty years into business casual, many Americans live without dress belts or socks; some don’t even have an iron, and even more don’t use the one they do have. The infiltration of casual clothes into the American wardrobe is complete, but standards are ever changing. Driving the change today is a generation of Americans who are less beholden to rules like “no white shoes after Labor Day.” Consultants say that as workers, Millennials “tend to be uncomfortable in rigid corporate structures,” value “a flexible approach to work,” and seek “similar things in an employee brand as they do in a consumer brand.” Today’s young workers didn’t have to shake off the shackles of formality that plagued the previous generation; clothing for them is less about fitting in than standing out. Clothing has always been personal—after all, we wear it on our bodies—but everyday fashion is moving toward the idea that people can wear what they want, as long as it is authentically them. This principle will define what people wear to work in the coming decade.

There’s always a pushback as dress standards change. Many today might be tempted to watch an episode of Mad Men and think, “Why don’t people dress that nicely anymore?” But clothing standards are born of their time and place. What people wear is dynamic, but not capricious. So anyone who frowns upon the hoodie-wearing coworker one cubicle over would be well advised not to judge. If history is any indication, that’s what everyone will be coming to work in soon enough.