A good leather jacket or bag is not a finished object when it leaves the workshop. It is the beginning of a long conversation between the material and the person who owns it. How you care for it decides whether that conversation lasts five years or fifty. The good news is that heritage leather asks for very little, as long as you give it the right things at the right time.
Begin with the simplest rule: let it breathe. Leather is skin, and skin does not like to be sealed in plastic or crammed into a damp cupboard. Store your pieces on a wide, shaped hanger or stuffed lightly with paper, in a cotton bag, somewhere cool and dry. Keep them away from radiators and direct sun, which draw out the natural oils and leave the surface tight and brittle. In Japan, where summer humidity can be punishing, many collectors keep a small box of desiccant nearby and air their leather on dry days. It is a quiet habit, and it prevents most of the mould problems people blame on the leather itself.
Cleaning should be gentle and infrequent. A soft horsehair brush or a dry cloth removes dust and grit, which act like fine sandpaper in the creases. For marks, a barely damp cloth is usually enough. Avoid household cleaners, wipes and anything with a strong smell. Vegetable-tanned leather, the kind made in the tanneries of Kasur and Sialkot and by the small Japanese tanneries we have written about before, is especially open and absorbent. It drinks in whatever touches it, which is exactly why it develops such a rich patina, and exactly why it deserves restraint.
Conditioning is where most people go wrong, and it is almost always by doing too much. Leather does not need feeding every month. Once or twice a year, a thin layer of a good natural balm, worked in with the fingertips and left to settle overnight, is plenty. Too much oil clogs the pores, softens the structure and darkens the surface unevenly. If you cannot remember when you last conditioned a piece, look at it honestly. If it still feels supple and looks alive, leave it alone.
Water is the other fear, but it is less dangerous than its reputation. A shower will not ruin a well-made jacket. What matters is what comes after. Let it dry slowly at room temperature, on a hanger, far from any heater. Hurrying it with a hairdryer is the single fastest way to crack a good hide. Scratches, scuffs and a few water marks are simply part of the record, and the Japanese idea of wabi-sabi would say they are the point.
There is a word in Japanese, mono no aware, for the gentle awareness that all things pass. Caring for leather is a small daily practice of it. You are not trying to keep the piece in a state of showroom perfection. You are helping it age well, so that the creases, the colour and the softness tell the story of the years you spent together. Brush it, rest it, condition it sparingly, and then wear it. Leather that is worn and looked after will always outlast leather that is merely protected.