It's an uncomfortable realization.
The woman walking toward you, who, at a distance, with her mid-thigh skirt and swan-diving V-neck, appeared to be 25, turns out to be 25 years older than that. "Yikes," you think, "such desperation. The world's a minefield for women over 40 trying to dress youthfully." Then you think, "Thanks again, Y chromosome, for one less thing to fret over."

But allow us to puncture that sense of security. Recently, as we've noted in these pages, men have shown themselves to be just as eager as the fairer sex to cling to the vestments of their youth—or to co-opt the vestments of today's youth. And in ever-more-misbegotten ways. We now have a small army of male archetypes suffering sartorial midlife crises.

There's the man still padding around dressed like the 28-year-old Silver Lake hipster—Vans, Daft Punk tee, thigh-hugging jeans—he was a decade ago. His proliferation is easy to understand, because his style requires no effort. Change nothing. No wonder he has numerous stuck-in-time siblings, like his urban-styled brethren.

"I'm picturing a guy in overly washed jeans and a baseball cap and sneakers," says Tommy Ton, a noted street-style photographer and chronicler of men's fashion. "It's one thing to wear sneakers in a dressy but casual way—it's another thing to take streetwear to an extreme once you're past 35."

Other types put in more effort. Effort on the scale of micro-lapel jackets on top of floral-print shirts on top of ruler-thin camo-print ties on top of Turk's-head-knot cuffs on top of a tangle of bracelets on top of purple plastic Wayfarers. And yet, under all this, a man can still look very obviously middle-aged (like our friend to the right here). This type of trend cluster has the same effect as a plastic-surgery pile-up: It makes him look not just old but afraid of being old. A close relative of this fashion fanboy is the svelte 32-year-old wearing a shin-skimming Thom Browne two-piece. Only he's 43 now—and his schoolboy-suit look comes off as such an exaggerated attempt to appear youthful he might as well be holding a giant swirly lollipop instead of a leather briefcase.

"There's a huge difference between looking current and looking trendy," says Ilaria Urbinati, a Los Angeles–based stylist who has dressed Bradley Cooper and Bruce Willis, among others. "As you get older, you have to do trends more simply—no bells and whistles."

Her words would seem to fall on the deaf ears of the aging rocker. Except this guy isn't an aging rocker. And he's not even Justin Theroux. He's just a man who dressed unremarkably in his thirties but when he slid north of 40 decided to put up some walls between himself and time—tight black T-shirts, biker boots, earrings, and skull rings. It's not even so much that this look itself is young; it's that the older a guy gets, the more it comes off as a flagrant attempt to preserve a badassness that he seems to think is endemic to youth. (Who is he thinking of? Justin Bieber?)

So what, exactly, is driving this persistent denial? After all, it's not new that our culture prizes youth over intelligence and accomplishment. Maybe today's man is swept along by the same current that makes it socially acceptable for gray-templed guys to use "totes" and "FTW" in texts. Maybe it's that as we've learned how to take better care of ourselves, 40 has become the new 30 and 50 the new 35 and 60 the new 40. Or maybe it's just old-fashioned obliviousness, aided and abetted by all of the above.

"As a guy, you have to figure out at an early age what works for you and be monogamous with it," says Michael Williams, founder of the men's style site A Continuous Lean. "I think guys dressing younger than they are skipped this developmental phase. They haven't figured it out."

They should. Bad style doesn't discriminate. What it does do, kind of like coke-snorting and clubbing, is get much, much less cute as you age. "When you're young and you dress too trendy, you look like a schmuck," Urbinati says. "When you're older and you dress too trendy, you look like an even bigger schmuck."

And if the reality check involved in weeding the age-inappropriate looks from your wardrobe stings that much, take heart: Once you turn 80, you can dress however the hell you want.