From their inception, tech companies went out of their way to be different - and that meant no more business suits. Thus brilliant innovations took place in the dumpiest of outfits as leather sandals, elastic-waist jeans and old T-shirts became ubiquitous.
But that's changing as a younger generation of engineers and designers have arrived seeking clothes that coordinate.
"There's definitely a shift happening here, and the age of the Silicon Valley culture has something to do with it," said image professional Joseph Rosenfeld.
"As a generation," he said, young professionals "tend to care more about style than engineers of the past."
The market has responded to this new attitude among the region's rising nerds, geeks and hackers with new online men's stores, personal style consultants and an array of high-end shops at Northern California's biggest mall. They're catering to the emerging members of a creative industry who, nonetheless, are seeking something of a uniform.
"They'll typically wear designer denim and a great button-up shirt by day, and throw on a sport coat at night to go to a cigar or wine bar," said Westfield Valley Fair mall general manager Matt Ehrie. "Silicon Valley's dressy attire would be casual Friday in most other parts of the country."
Josh Meyer, 30, a products manager at a leading high-tech firm, recognizes the generation gap. He said higher-level managers who have been in the industry for decades often wear baggy khakis and faded baseball shirts "like they're going to a barbeque," while millennials such as himself like to wear button-up dress shirts "high-quality denim jeans with a roll at the bottom, nice shoes or possibly boots."
"I can pick out techies just walking down the street by these outfits," he said.
The focus on men's fashion has emerged in a sector where 3 of 4 workers are males. And it's come late by comparison as women in technology have long faced style challenges.
Many have worked to strike a casual, professional and creative balance, even as blogs and news stories regularly focus on the image of female high-tech executives - from the extraordinarily stylish Yahoo CEO Marissa Mayer, featured in last month's Vogue, to Facebook's uber-chic chief operating officer Sheryl Sandberg.
Meanwhile, when men are similarly featured attention often shifts to casual attire - from Facebook CEO Mark Zuckerberg's famous hoodie to former Apple CEO Steve Jobs' black turtleneck.
"As much as we want to think there isn't a boys club, the Silicon Valley still feels very much run by men and there's a difference in expectations," says San Mateo-based image consultant Marina Sarmiento Feehan. "Women who rise to the top tend to be judged more, both by men and other women, and in order to succeed they do have to dress better."
With the nation's highest concentration of high-tech workers, accounting for almost a third of the jobs in the region, demographics show a younger, more affluent population than national averages. Newcomers tend to have the desire and the money to dress well, but they don't always have the time, so the men's fashion industry has responded by streamlining the process.
Erik Schnakenberg, founder and CEO of a new online men's store, Buck Mason, said his company focuses on "guys who want to look great, who are aware of style, and who are not going to spend their days in Bloomingdale's trying to find the newest piece. Tech guys are at the top of that list."
Buck Mason client Peter Dering is a firsthand example. When Dering launched his online startup Peek Design, which innovates and builds camera accessories, he worked marathon hours and had no time to shop. Still, he had both a personal and professional interest in looking sharp as he was raising $1.5 million and trying to hire top talent.
"You've got a lot of folks who think that their style doesn't matter because they sit behind a desk all day, but the fact of the matter is that it does make a difference," said Dering, noting that people who want to be taken seriously should dress appropriately.
Buck Mason sells American-made clothes in packages of matching neutral outfits, enough to dress a software engineer for a week with no fashion faux pas, and targets it's advertising online. The Silicon Valley is the company's top region for sales, Schnakenberg said.
Also working to accommodate techies, one of the country's best-performing malls, Westfield Valley Fair, has opened high-end men's stores this year, including Prada, Salvatore Ferragamo, Burberry and Louis Vuitton. The shops are grouped together with a separate outside entrance so shoppers don't have to fight past teens clogging the food court. And until now, such stores were mostly an hour away in San Francisco.
The change in the Silicon Valley men's fashion culture has made things interesting for image professionals such as Rosenfeld. For 13 years he was mostly a loner advising area professionals, but in recent months competitors have popped up, including ties + tees, a pair of Silicon Valley personal image consultants whose pitch includes, "The 90s called. They want their drab khakis back."
Still, Rosenfeld welcomes the new focus on fashion. "Birkenstocks with white socks was hideous back then, and it hasn't gotten any better," he said. "It's time to up the ante."