Every attribute on a bag that changed over time is a dating instrument, which is the founding idea of this entire site. The serial formats changed, so the tools exist. The logos changed, the linings changed, the hardware changed. But there is one attribute that changed more dramatically than any of them, that every listing shows in the very first photograph, and that almost nobody thinks to read as evidence: the size. Handbags spent one era inflating and the next era shrinking, the swing was violent, and the pendulum left timestamps all over the files.
The big era
The 2000s were the decade of the enormous bag. The It-bag economy that the Baguette invented in miniature was, within a few years, running entirely on bulk: slouchy, swallowing, carried-in-the-crook-of-the-arm bags that treated cargo capacity as glamour. Two of this site's files are natives of that era and carry its proportions in their bones. The Fendi Spy of 2005 is a soft duffel of a thing, all volume and slouch. The Balenciaga City is a long-winged rectangle built to look already packed. The tote grew until it was luggage, the hobo grew until it was bedding, and for the better part of a decade the default adjective in a handbag description was oversized. If a design was born in those years, it was born big, and its smaller sizes, where they exist at all, almost always came later. Hold that thought.
The snap
Then the pendulum did not swing back so much as snap. In the late 2010s a three-inch bag from Jacquemus called Le Chiquito became the most photographed accessory in fashion, and I note with professional delight that the references cannot even agree which season it debuted in: fall 2017, spring 2018 and 2018 generally are all in print, a dating dispute about the dating landmark itself, which feels like this site's entire worldview getting a wink from the universe. The follow-up Le Petit Chiquito of fall 2019 measured two inches. By the turn of the decade every house had answered: minis, micros, nanos, bags for a card and a key and nothing else, and the luxury wave of the early 2020s put the shrink ray on the archive itself. The Prada Re-Edition is the cleanest specimen in the files, a revival whose whole premise is a smaller, trend-sized rebirth of the vintage nylon hobo. The revived Baguette came back with nano-class siblings its 1997 original never had. Even the Jackie returned with a size run its namesake decade would not have recognized. The micro era's emblems are other houses' bags, but its fingerprints are all over this site's maisons.
Why the pendulum swings
Three honest reasons, briefly. The phone emptied the handbag: once the wallet, the camera, the diary and the map collapsed into one object, cargo stopped being the point. The photograph replaced the errand as the bag's natural habitat, and a tiny bag reads beautifully at feed resolution. And, least romantic and most important, the mini is revival economics: a smaller size of an icon is a brand-new product with a decades-old name and a friendlier price, the entry ticket to a house. Which is exactly why the minis cluster where they do in the files: the small sizes arrive with the comebacks, because the small size often is the comeback. The whole roster of returns is in the Comeback File, and it reads, size column included, like the pendulum's own diary.
The dating instrument
Here is the part that makes this a case file instead of a trend piece. Size variants have birthdays. A maison does not launch every size at once: the big-era natives were born big, the minis and micros overwhelmingly enter the files in the revival era, and the gap between a design's birth and its smallest sibling's birth is often measured in decades. So the silhouette runs the same check the tools run on serials: the era must agree with the model's own file. A nano version of a bag being sold as a 1990s original is a contradiction you can see from across the room, before any code is photographed, because that size did not exist in that century. It is Date First doctrine applied to the one attribute no seller can crop out. The honest exception proves the rule: the Kelly and the Birkin have carried numbered size families for generations, so at Hermes a small bag dates nothing by itself and the work stays with the blind stamp and the hands of a professional. Everywhere else, the pendulum timestamps the inventory.
The counterfeiters read the pendulum too
One warning, carried over from the Counterfeiters' Favorite: the fake trade follows fashion faster than it follows factories. When the market wants minis, the fakers cut minis, including mini versions of models whose real houses never made one in the era being claimed. A trend-sized fake of a vintage design is the counterfeit equivalent of a 1950s photograph with a smartphone in it, and once you start reading size as a date, these anachronisms light up on their own.
The verdict
So the buying order gains a step at the front. Before the code, before the receipt, before the stitching: read the silhouette, and ask whether this size, of this model, existed in the year being claimed. The model files on this site record the birthdays; the swing of the pendulum is why those birthdays cluster the way they do. And the pendulum has not stopped. The same press that buried the big bag spent the early 2020s predicting its return, with the City itself named among the resurrections, which means somewhere ahead is an oversized revival whose minis will one day confuse a listing in 2040. The sizes will keep changing. That is not a problem for a buyer. On this site, change is the whole instrument.