WHEN it comes to clothes, I've always been kind of allergic to retail trends.

All those neat stacks of the same focus group-approved tank top overwhelm me. I get hives just walking past Forever 21.

There’s also the tinnitus that I’m pretty sure is the sewing machine hum of the Bangladeshi children churning out T-shirts for Old Navy.

For reasons ethical, aesthetic and economic, I prefer scrounging for my look: Sale racks, thrift shops, discount barns, living room swaps and fashionable friends’ closets have yielded some of my best vestments, allowing me to cultivate a wardrobe I like to call “pragmatic costume chic.”

My favorite places are the ones that do the foraging for me, collecting the weird wonders and one-of-a-kinds and buying from the customers themselves.

That way, when your duds depress you, you can pack ‘em up and trade out for another new-to-you trousseau (minus a 50 percent commission, natch.)

I honed this sartorial cycle as a college student in Tucson at Buffalo Exchange, where a young Robyn Reeder was using her artistic gifts to sort through the Jessica McClintock frocks and Girbaud jeans.

I didn’t know Robyn back then, but I may have a fuzzy memory of a petite blond pixie rejecting my tote of Flashdance-cut sweatshirts sweetly but firmly, like only the Buffalo Exchange girls could.

In a stroke of fabulous obviously orchestrated by the fashion gods, this loop de couture has continued in Savannah at Civvies, Robyn’s legendary new-and-recycled clothing emporium on Broughton. Yes, the serendipity is momentous, but when you’ve bought the same teal romper 25 years apart, it comes as no surprise that life, like fashion, is just a magical, rhinestone-studded circle (see last week’s cover story about Robyn, and also, the comeback of shoulder pads.)

All the cool kids know this wonderland of vintage scores, trendy apparel and cheap sunglasses, and nothing illustrates Civvies’ cross-cultural, multi-generational appeal more than running into your teenage son perusing the racks.

“Eww,” mine hissed when he saw me. “What are you doing here?”

Awkward! I mean, not for me, but I could see him trying to wrap his mind around the irreconcilable irony of shopping at the same store as your mom and actually wanting to.

Suck up the paradox, son; one day you’ll wish I’d kept your dad’s boxy Structure sportcoat from the ‘90s.

Many fashionistas and fashionistos already know that Civvies jumped another level on the cosmic spiral this month when it moved from its upstairs aerie to a new nest three doors down, which happens to be in the same building Robyn and Amy Spurlock started their first business, Primary Art Supply.

Shoppers now thread their way through the funky antiques of Really Great Finds to the back stairs, making it feel like you’ve entered Norma Desmond’s Hollywood mansion to shop the most epic closet in town.

The reincarnated space is longer and narrower than its predecessor but translates the shop’s signature punky-go-lucky vibe. Its shelves are full of fanny packs and fur coats and felted wool bowlers with cat ears, the round racks categorized by color like candy. And because even the heaviest of Sebastian Edwards’ custom-built furniture only had to be moved down the block, the changeover was as quick and seamless as mending a hem.

“Somehow, we didn’t even close for a day!” exclaims assistant manager Emily Boutwell. “The customers didn’t even have a chance to complain!”

Everything’s been business as (un)usual, but what would you expect from a place that proudly disrupts the space time continuum with 70 years’ worth of fashion all at once? There’s great power in that circuit, and the whole place just might levitate during Civvies’ Grand Opening Party on Thursday, July 23.

Yes, that’s next Thursday; we want to make sure you have plenty of time to plan your outfit. The theme is “Vintage Flight,” so think sexy stewardess dresses and Mad Men pilot caps, Hawaiian shirts and Bermuda shorts, space helmets and poodle skirts.

Heading up the entertainment is COEDS, the four-piece ensemble fronted by my Connect cubicle mate and “ruckus ‘n’ roll” goddess Anna Chandler, who writes about everyone else’s band by day and shreds her own fast and dirty guitar licks by night.

Rounded out by Phillip Price, Jeremiah Stuard and Donald Moats, COEDS also straddles the decades with driving iterations of doo-wop punk pop that may have “snuck a handle of whiskey into the sock hop.”

The quartet just finished recording their first LP this summer, and because I share a padded half-wall with Anna, I got a preview listen that had me bouncing. I’m no music writer, but I think it’s what might happen if you poured Dusty Springfield, the Clash and a Cuba Libre into a packet of Pop Rocks and shook vigorously.

Folksy lounge iguanas Carpet Coats (hey, where do l buy one of those for winter?!) will open the evening’s festivities, and stacks of the hand-drawn music ‘zine the clambake will be for sale. Snacks, drinks and deep discounts are also on the menu.

It’s bound to be a swanky blast as we welcome the city’s original clothing exchange to the next plane, but the atmosphere doesn’t come without a bittersweet tang.

As Anna’s story detailed last week, Robyn has lived with cancer for more than a decade, and she’s overseen Civvies’ latest shift with the knowledge that she may make her greatest transition sooner than later.

For building owner and friend Tony Chastulik, the opportunity to absorb the shop was a no-brainer.

“Partly, it was a business decision, since having Civvies in the building and the big marquee gives us a more pronounced presence on Broughton,” says Tony.

“And then, of course, it’s Robyn,” he adds with a small break in his voice. “I’m trying very hard to save her. I don’t want to let her go.”

When asked how many years he’s given Civvies’ on its new lease, Tony replies, “Indefinitely.”

That seems like perfectly appropriate for a store that transcends time itself, maybe even long enough for my kid to have his own children pretend not to know him when he encounters them going gaga over a pair of Dockers.

But whatever trend comes round again, I’ll bet my vintage orange combat boots that Robyn Reeder’s fashion legacy never, ever goes out of style.