Cost per wear: the only shopping math you need

Price tells you what a piece costs to buy. Cost per wear tells you what it costs to own, which is the number that decides whether it was worth it. It is the simplest useful piece of wardrobe math there is, and it changes how you shop more than any style rule.

The formula

Cost per wear = price paid ÷ number of times worn. That is all of it. A $120 pair of boots worn 60 times costs $2 per wear. A $25 top worn once costs $25 per wear. The boots were the cheaper purchase.

Worked examples

These are made-up round numbers to show how the math behaves, not averages from anywhere.

• Everyday jeans. $90, worn twice a week for a year, about 100 wears: $0.90 per wear.
• A winter coat. $300, worn five days a week for four months, about 80 wears: $3.75 per wear. By the second winter it is under $2.
• A party dress. $150, worn twice: $75 per wear. It would need fifteen more outings just to match the coat.
• A sale sweater. $20, bought because it was $20, worn once: $20 per wear, and it is taking up a hanger.

The pattern: pieces you can wear often are almost always cheaper to own than pieces you buy for one scenario, regardless of the price tag.

What counts as a wear

A full day, or an evening out. A piece you changed out of after twenty minutes because it didn't feel right doesn't count, and that is useful information too. Be consistent rather than precise; the number is for comparison, not accounting.

How to track it without a spreadsheet

The reason most people never use cost per wear is that the "wears" half needs counting. Two things make it painless:

1. Add the price once. When you add a piece to your digital wardrobe, enter what you paid, roughly if you don't remember. In iDrobe, price and currency are a field on the item, next to the brand.
2. Log wears in one tap. Mark "I wore this" on the piece or on the day's outfit, or log a try-on look as what you wore. Insights then keeps a running cost per wear for every priced piece and sorts them from best value to worst.

After a month you will have a list that is often surprising. The expensive things you were sheepish about are usually near the top; the impulse buys are at the bottom.

Using it before you buy

The formula also works forward. Before checkout, estimate how many times you will realistically wear the piece in the next year, then halve your first answer, because everyone is an optimist at checkout. Divide the price by that number and compare it with the pieces in your wardrobe it would replace or compete with.

• If the estimated cost per wear is in the same range as your most-worn pieces, it is likely a good buy.
• If you can't picture ten wears, it is an occasion piece. Occasion pieces are fine, as long as you know that is what you are buying.
• If the piece needs another purchase to be wearable (the shoes, the belt, the right bra), add that to the price.

iDrobe carries this across: a piece you save from Scout keeps its price on the wishlist, so when you mark it as bought, cost per wear starts counting from day one.

When the expensive piece is the cheap one

Cost per wear rewards three things: fit, versatility and durability. A well-cut coat in a neutral color that goes over everything will be worn through two or three winters. A pair of leather shoes that can be resoled outlasts several pairs that can't. A plain cashmere sweater gets worn fifty times a winter; the statement version with the big motif gets worn five. If a piece scores on all three, paying more for it tends to lower its cost per wear, not raise it.

A few rules of thumb

• Anything under about $1 per wear is a wardrobe workhorse. Buy its replacement before it dies.
• Anything you have owned for a year with a cost per wear still at its full price was a mistake. Sell it, give it away, or plan a week around it.
• Basics should trend toward zero. Occasion pieces will stay high; keep them few.

Cost per wear is the backbone of a capsule wardrobe that actually gets worn, and the third question in the five-question test before checkout.