A fitted leather jacket only works over a t-shirt, which makes it useless for most of the months you would want to wear leather. A roomier cut takes a knit underneath without straining the seams. That single change turns a spring piece into an autumn one. The leather jacket spent forty years locked into a Schott-derived moto shape that flattered a narrow range of bodies. Dropping the shoulder is the first real change to the category since the 1980s.

Thin leather drapes softly and looks cheap under any light, while heavier hides hold a shoulder line and improve with wear. The oversized cut exposes this immediately because there is more surface to sag. Feel the jacket sleeve before anything else. Weight is the honest quality signal in leather and it is detectable in about three seconds. Thin hide drapes softly and reads cheap under any light.

The leather jacket descends from two separate pieces of equipment, the aviator flight jacket of the 1910s and the motorcycle jacket Schott introduced in 1928. Everything on sale is a variation on one or the other, and the oversized cut sits closer to the flight jacket lineage with its wider body and dropped shoulder. Punk and rock claimed the motorcycle version so thoroughly that it still carries that reference whatever you do with it. The looser jacket reads quieter for exactly that reason, since it borrows from the less loaded of the two. Choosing between them is choosing which century of workwear to reference.

Lambskin is soft immediately and thins out at the elbows within a few years, while cowhide and horsehide start stiff and last decades. Vegetable-tanned leather develops a patina that darkens where it is handled, and chrome-tanned leather stays largely as it started. A jacket in a heavier hide will feel like a mistake for the first month and then begin fitting only you, which is the entire argument for buying one. Avoid anything described as bonded or coated, since both are ground leather scrap on a backing and split rather than crease. The weight in your hand at the shop is a fair predictor of the next ten years.

Size up once from your blazer size rather than twice, because an oversized leather jacket that swamps the frame reads as an accident. The drop should land just past the shoulder. Deliberate is the difference. One size up reads deliberate and two reads accidental, which is a narrower margin than most people assume. The drop should land just past the shoulder.