Why do denim and leather get better with age?

8 min read

Wide jeans, a slightly oversized leather jacket, black leather shoes. A combination you've seen for years, and yet it doesn't look dated.

Most clothes look their best on the day you buy them and age from there. Denim and leather go the other way: the more you wear them, the more they learn the shape of your body and become yours.

Is that just a vibe? Looking at how the dye works, material tests, environmental assessments, and research on attachment, it turns out there are real reasons.

Denim fading is designed in

Denim is a twill weave of indigo-dyed warp threads and undyed white weft threads. The blue warp shows mostly on the front, and the back looks whitish.

The indigo doesn't soak all the way into the yarn; only the outside is dyed. This is called rope dyeing, which leaves a white core ("ring dyeing"). So when the surface dye rubs or washes off, the white inside slowly shows through [3].

Behind the knees, at the top of the thighs, the shape of a wallet in a pocket. Where the color fades is decided by how that person sits and walks. Fading isn't deterioration; it's built from the start to become a record of the wearer.

The anthropologists Daniel Miller and Sophie Woodward wrote that on any given day, a large share of the world's people may be wearing jeans, a garment so ordinary that hardly anyone had thought to study it [4]. Everyone wears them, and yet no two pairs end up the same color. That's what I find fascinating about denim.

Leather still has no real substitute

A German research institute tested shoe-grade cowhide, synthetic leather, and nine "alternative leathers" made from things like cactus, pineapple, and apple under the same conditions [5].

The result: no material other than leather combined strength, resistance to flexing, and breathability (water vapor permeability). Some materials scored highly on particular measures, but not on all of them. And many of the alternatives contained plastics such as polyurethane.

Leather is animal hide whose collagen fibers are tangled together in three dimensions. That network gives it both strength and the ability to let air and moisture through. A leather jacket creasing along your movements, with the elbows and shoulders taking your shape, comes from those fibers slowly stretching and settling.

Clothes you wear longer are better for the environment

In 2015, Levi Strauss published a life cycle assessment following one pair of 501 jeans through its whole life. From growing the cotton to disposal, one pair used 3,781 liters of water and produced 33.4 kg of greenhouse gases (CO₂ equivalent). 68% of the water went to growing cotton and 23% to washing and care after purchase; for greenhouse gases, care after purchase accounted for 37% [1].

The same assessment says that washing every 10 wears instead of every 2 can cut the water, energy, and climate impact of the use phase by up to 80%. It's the company's own assessment, so it should be read with some caution, but "don't over-wash" is good for both the color of your denim and the environment.

Even bigger is wearing clothes longer. A report from the UK nonprofit WRAP estimated that clothes are worn for about 2.2 years on average, and that extending that by just nine months would cut the carbon, water, and waste footprints by 20–30% each [2].

Meanwhile, according to a report from the Ellen MacArthur Foundation, global clothing production roughly doubled from 2000 to 2015, while the number of times a garment is worn before being discarded fell by 36% [6]. We have more clothes, and wear each one less.

Compare environmental impact by material alone, and clothes thrown away quickly get treated the same as clothes worn for years. Researchers at Oslo Metropolitan University have criticized material-comparison tools for ignoring the use phase [7]. That's where the value of denim and leather you can wear for years shows up.

Unwashed jeans aren't as dirty as you'd think

At the University of Alberta in Canada, a student wore the same jeans for 15 months without washing them, and a textile sciences professor tested them for bacteria. Even in the crotch, where bacteria were most numerous, the count was about 8,000–10,000 per square centimeter, almost the same as after two weeks of wear following a wash. What they found were ordinary skin bacteria [8].

But this was an observation of one person and one pair, not a peer-reviewed study. The student also said the smell became noticeable after a few months. The right reading is that you don't need to wash them every time: wash when you've sweated, or when they start to smell.

People take care of clothes that have aged with them

Mugge and colleagues at Delft University of Technology in the Netherlands showed that when people become attached to a product, they handle it with care, repair it when it breaks, and put off replacing it. As one of the factors that creates attachment, they named the time spent with the product and the memories attached to it [9].

The fading on denim and the creases in leather are exactly the traces of that time. The crease at the elbow from last winter isn't on anyone else's jacket. That's why it's hard to let go of, and because you don't let go, you wear it longer. The nature of the material and the workings of the heart point in the same direction.

In "Refined taste makes it harder to be satisfied," I wrote about how knowing good things makes it harder to be satisfied. But clothes that grow with you are a bit different. Instead of adding new stimulation, you find differences within the same thing, so you're less likely to tire of it.

The weak points

• Cotton uses a lot of water: nearly 70% of a pair of jeans' water goes to growing cotton [1]. That's exactly why buying fewer pairs and wearing them longer matters
• Leather's environmental impact is disputed: results change a lot depending on how much of the burden of raising cattle is assigned to the leather, and how the tanning process is managed
• Heavy and needs care: leather doesn't like rain and cracks when it dries out. It needs conditioning cream from time to time
• Stiff at first: both take time to break in. Whether you can enjoy that time decides whether they're for you

How to wear them: fewer colors

The combinations that work, the ones you see on the street, have something in common: give room to either the top or the bottom, and keep it to two or three colors.

In each, the star is the texture of denim and leather, not color or pattern. That's why they're slow to look dated when trends change. And after a few years of wear, the same combination looks better than it did on the day you bought it.

Rather than adding more and more new clothes, take one pair of jeans and one leather jacket and make them your shape over a long time. I think that's a good way to own clothes.