A good leather jacket is not a seasonal purchase, it is something you wear for decades. With a few simple habits it will age beautifully and develop a character no new jacket can copy.
Wipe it down with a soft, slightly damp cloth after wearing, especially in humid or dusty weather. Never use harsh soaps or household cleaners, they strip the natural oils from the hide.
Condition it twice a year
Apply a thin layer of leather conditioner with a clean cloth, work it in with small circles and let it rest overnight. This keeps the fibres flexible and stops cracking around the collar and cuffs.
Store it properly
Hang it on a wide, padded hanger in a cool, dry wardrobe. Avoid plastic covers, leather needs to breathe. If it gets wet, let it dry naturally away from heaters or direct sun.