One decade, this accessory is déclassé, the epitome of corny. Next decade, it's a precious must-have. Really?

The trendlet

In a nutshell, that's the story of the fanny pack. For some hipsters and high-fashionistas, it's the go-to for holding keys, lipsticks, and oversize smartphones for quick, selfie retrieval. But runners - especially today's Philadelphia Marathoners - rely on the waist pouch to hold tissues, iPods, and energy gels.

Where's it come from?

Pouches attached to belts go back to medieval times and also were a part of traditional American Indian dress. Then there were holsters that held guns and bullets instead of spare change.

In the late 1970s, mysterious, made-from-vinyl satchels began appearing on belts, and they shifted so they literally sat on fannies.

By the 1980s, workout gurus - specifically Richard Simmons - were proponents of fanny packs, which became associated with tourists and outdated sweatsuits. Tacky.

In 2001, the fictional Carrie Bradshaw wore a Gucci fanny pack on Sex and the City. By 2005, luxury brands Louis Vuitton and Marc Jacobs were producing fanny packs, and Le Sportsac did a vinyl version for more sporty divas. It never really caught on.

However, by 2014, now inspired by athleticism and tech, companies like Chanel, Alexander Wang, Rebecca Minkoff, and Coach featured fanny packs in their collections. American Apparel introduced moderately priced ones for people who like a pop of color over yoga pants. In August, stylish dad Matthew McConaughey defended the merits of a black fanny pack he wore at a Boston baseball game with his son.

Who's wearing it?

In the last year, fanny packs have run rampant on celebrity hips: Rihanna was spotted in a Joy Rich Cash Flow; Fergie prefers the chain-link, quilted Chanel. And Jared Leto, the man who made man-buns famous, is a fan. (Who made Leto a trendsetter again?)

Would Elizabeth wear one?

I'd like to try a sporty, hip-hugging fanny pack. But I can't bring myself to do it. I gravitate toward a cross-body purse to run my errands hands-free.

Should you wear one?

I can't deny the fanny pack's practicality. But pay attention to where you wear it. We suggest right on the hips. Pop that baby around your waist, and you might as well just kill your fashionable vibe.

215-854-2704@ewellingtonphl

Ski jacket fanny pack, Moschino, $225; gray two-pocket, Jas M.B., $125, both at Joan Shepp, 1811 Chestnut St., 215-735-2666, www.joanshepp.com; brown canvass, Il Bisonte, $354, at Knit Wit, 1729 Chestnut St., 215-564-4760.