Cost Per Wear
There's one math equation that quietly changes how you shop forever. It's called cost-per-wear, and once you've used it three times you can never un-see it.
The equation
Cost per wear (CPW) = total cost of an item ÷ number of times you wear it.
That's it. One number, total honesty.
A $200 wool sweater you wear 100 times costs you $2 per wear. A $20 fast-fashion top you wear 4 times costs you $5 per wear. The cheap thing was actually 2.5x more expensive per use.
The trick is that price tags lie. They tell you the cost at the moment of buying — not the cost across the item's life. CPW gives you the real number. It's the same kind of math grown-ups use when they ask 'cost per square foot' on a house, or 'cost per mile' on a car.
Why this changes everything
When you start using cost per wear, three things happen.
1. You stop being scared of higher price tags. A $150 pair of Levi's 501s that lasts 7 years often costs less per wear than the four $40 jeans you'll burn through in the same time.
2. You start asking 'will I actually wear this 30 times?' before buying. The activist Livia Firth made this famous as the '30 wears test'. If the honest answer is no, don't buy it.
3. You notice that some categories deserve splurging (everyday basics, coats, shoes) and others don't (one-off party outfits, trend pieces).
The goal isn't to spend more. It's to spend better.
Real CPW examples
Here are real, normal examples (not fancy designer math):
- A $35 Shein dress worn 3 times to one school dance and never again: $11.67 per wear. - A $80 pair of Vans worn 4 times a week for 2 years (~400 wears): $0.20 per wear. - A $300 winter coat worn every winter day for 6 years (~720 wears): $0.42 per wear. - A $25 trendy crop top worn twice and outgrown: $12.50 per wear. - A $60 backpack used daily for a school year (~180 wears): $0.33 per wear.
Notice that durability and frequency matter more than the sticker price. The most 'expensive' looking thing on this list (the coat) had the second-lowest CPW.
When CPW gets tricky
CPW isn't perfect. A few honest catches:
- It's hard to predict wears in advance. Estimate honestly: would you wear it weekly, monthly, or once? - Quality is hard to assess from a webpage. Look at fabric content, stitching photos, and reviews mentioning longevity. - It only counts your wallet, not the planet. A $5 t-shirt with a CPW of $0.10 still cost the planet 2,700 litres of water and possibly underpaid a worker.
The full version of CPW that sustainability-focused designers use also includes 'cost per wear to the planet.' We'll go deeper into that in the Lifecycle course. For now, even just doing wallet-CPW is a huge upgrade from how most people shop.
Key takeaways
- Cost per wear (CPW) = total cost ÷ number of wears.
- A $200 sweater worn 100 times beats a $20 top worn 4 times — $2 vs $5 per wear.
- The '30 wears test' (Livia Firth): if you wouldn't wear it 30 times, don't buy it.
- Splurge on basics, coats, and shoes. Skip splurging on one-off trend pieces.
- CPW only counts your money — it doesn't capture the cost to the planet or workers.
Try this
Calculate your top 5
Pick 5 items in your wardrobe — your most-worn AND your least-worn. Estimate the cost of each and the number of times worn. Calculate cost per wear. Which item is the cheapest per wear? Which is the most expensive? Are you surprised?
The 30-wears pledge
For your next 3 clothing purchases, before you check out, ask yourself out loud: 'Will I wear this at least 30 times?' If the honest answer is no, put it back. Track for one month how many items you DIDN'T buy because of this question. That's money saved AND waste avoided.
Family CPW debate
Pick one cheap item and one expensive item in your family's home — say, a $15 toaster and a $100 toaster. Calculate the cost per use over 5 years. Argue for the cheaper one. Then argue for the more expensive one. Which argument was easier? Why? CPW often turns out to favour quality, but not always.
What is the cost per wear of a $120 jacket worn 80 times?
$120 ÷ 80 wears = $1.50 per wear. Compare this to a $30 fast-fashion jacket worn 5 times ($6.00 per wear) and you can see why cost per wear often makes 'expensive' items the better deal.