To outsiders, spending $3,000 on a Cartier ring or a Louis Vuitton Handbag might seem outrageous. But if you know how secondhand luxury works, it’s not a splurge, it’s strategy.
I call it the Girl Math of Secondhand Luxury, a smarter, savvier way of thinking about luxury purchases. At its core is a simple idea: many luxury items reach a point where they stop depreciating in value. If you buy them at this point (what I call the “depreciation floor”), you can often wear and enjoy them for months—sometimes years—and then resell them for the same price you paid. Maybe even more.
It’s not just wishful thinking. It’s a pattern I’ve seen play out time and again: with my own purchases, with items I resell, and across countless listings on the secondhand market. It’s the sweet spot where fashion meets finance, and it’s surprisingly predictable once you know what to look for.
Let me show you how it works.
What Is Girl Math And Why It Actually Makes Sense
If you’ve spent any time on TikTok lately, you’ve probably come across girl math. It’s the kind of playful logic that makes it totally reasonable to buy a dress because you’ll “definitely wear it at least ten times,” or convinces you that spending £200 on skincare doesn’t count because you used Klarna.
It’s part joke, part genuine coping mechanism, and honestly, I love it. But here’s the thing: when it comes to secondhand luxury, girl math actually holds up. Because once you understand how resale value works, you realise that a $3,000 ring doesn’t really cost you $3,000.
Not if you buy smart.
There’s a point with certain pieces, Cartier rings, Chanel bags, Louis Vuitton totes, where they stop dropping in value. That’s what I mean by the depreciation floor. Once an item hits that price, it tends to stay there. Which means if you buy it at the right time, take good care of it, and sell it on later… you get your money back. Or at least most of it.
So yes, it’s girl math. But with secondhand luxury? It’s also pure logic.
The Depreciation Floor Theory (aka the Sweet Spot)
Here’s the secret most people don’t realise about secondhand luxury: the value of certain items doesn’t just fall endlessly after purchase. Instead, it drops to a certain point, and then it levels out.
That’s what I call the depreciation floor.
Once a piece hits this floor, its resale price tends to stay stable, sometimes for years. And in some cases, especially with classic or discontinued items, the price can even start to go back up.
Why does this happen?
There are a few reasons:
- Ongoing demand: Iconic items like Cartier rings, Chanel bags, and Louis Vuitton totes never really go out of style. There’s always someone looking to buy them, especially at secondhand prices.
- Limited availability: Many of these items are hard to get in-store, have long waitlists, or are regularly out of stock. That pushes more people to the resale market.
- Retail price increases: Luxury brands raise their prices all the time. What you bought for $1,500 three years ago might now retail for $2,200. That naturally pulls the resale value up too.
- Brand recognition: The most well-known names, Cartier, Chanel, Hermès, Louis Vuitton, tend to hold value better, because buyers trust the brand and the quality.
So if you know where that floor is, and you buy at or just above it, you can often resell the piece later for the same price. Sometimes more.
That’s why I always say: you’re not just buying a luxury item. You’re parking your money in it.
This isn’t just a theory I’ve read about. It’s something I’ve experienced first-hand, again and again. I’ve bought pieces, worn them, loved them, and then sold them on without losing money.
Here are a few real examples of how this plays out:
The Girl Math of a Cartier Love Ring
Let’s say you’re eyeing a Cartier Love Ring (classic model, yellow gold). Here’s how the girl math works out:
You just wore a $2,000 ring for a year, for the price of a takeaway. That’s not a splurge. That’s strategy.
The Girl Math of a Louis Vuitton Neverfull MM
Let’s apply the Girl Math of Secondhand Luxury to a Monogram Louis Vuitton Neverfull MM:
You carried a $2,000+ designer tote for over a year for less than the price of a mani-pedi. That’s not luxury guilt. That’s luxury logic.
How to Shop the Depreciation Floor (Without Getting Burned)
If you want to get the most out of the girl math of secondhand luxury, the key is buying smart. Not every piece holds its value, and not every resale price is a good deal. But once you know what to look for, it gets easier to spot the good buys, and avoid the overpriced ones.
Here’s how I approach it:
1. Stick to the classics
Go for items that always have demand. Think:
- Cartier Love rings and bracelets
- Louis Vuitton Monogram Neverfull, Speedy, or Pochette Métis
- Chanel Classic Flaps
- Hermès Kelly bags
These pieces are recognisable, in demand year-round, and rarely drop in value if kept in good condition.
2. Know the resale floor price
This comes with a bit of research (or experience), but you’ll start to see patterns quickly. Browse resale platforms like:
- Fashionphile
- The RealReal
- Rebag
- eBay (look at sold listings, not just what people are asking)
- Poshmark
Look at the lowest consistent prices for items in “Very Good” or “Excellent” condition, that’s your floor. If the same item keeps popping up around the same price point, that’s likely where the value has stabilised.
3. Buy below retail (but not too cheap)
If a deal looks too good to be true, it probably is. Sketchy sellers, fakes, and heavily damaged items are common in the lower price brackets. I personally avoid items marked as “Fair” or “Good” condition unless it’s something I know can be restored or easily resold.
4. Keep the extras (they matter)
Dust bags, boxes, receipts, and authenticity cards all add value when you go to resell. If you have the choice between two listings and one has the full set, it’s worth paying a little more. It’ll be easier to resell and hold its value better.
5. Be gentle with it
Use your pieces, but treat them well. Store your ring in the box when you’re not wearing it. Avoid tossing your bag on the floor of a café. Wipe down leather items. Little things like this keep the resale value high, even if you’ve used the item regularly.
Buying at the depreciation floor isn’t about hoarding pieces, it’s about creating a revolving closet of investment-worthy items. You enjoy the luxury, you hold onto your cash, and when you’re ready to let go? Someone else gets the chance to love it next.
Closing Thoughts: The Smartest Splurge You’ll Ever Make
I’ve worked with luxury goods for over 15 years, buying, selling, analysing price trends, and helping others shop smarter. I’ve watched the resale market evolve, and I’ve seen firsthand which pieces quietly hold their value while others crash and burn. What I’ve shared in this article isn’t a theory I pulled from a trend, it’s how I run my business and how I build my own wardrobe.
The truth is, when you understand the depreciation floor, secondhand luxury becomes something else entirely. It stops being an indulgence and becomes a form of asset-backed enjoyment. You’re wearing something beautiful and valuable, but unlike fast fashion or impulse buys, you’re not watching your money disappear. You’re simply holding onto it in a different form.
So yes, it’s girl math. But it’s also real strategy.
You get to enjoy the thing and keep the money. That’s the magic.
And once you see it in action, you’ll never look at a Cartier ring or Louis Vuitton tote the same way again.
Make sure to check out my in-depth buying guides. I break down exactly what to look for, what to avoid, and how to find the best pieces at the right price.