Leather's natural fibers will break down with time. That's why you should think of leather like you think of your skin. For your face to look its best, you've got to clean it and keep it hydrated. Your leather jacket's not that different. If your jacket's dirty, then you'll want to wipe it down with a slightly damp cloth and then let it dry at room temperature overnight. You want to make sure the leather is dry when you condition it. And you want to stay clear of creams and oils that contain waxes or silicones because they'll prevent the jacket from breathing—one of the advantages of leather outerwear.
Dampen a soft cloth with water and apply a quarter-sized amount of conditioner to the cloth.
Begin by rubbing in small circles, working your way over the entire jacket.
Remember that several lighter passes are better than one heavy-handed application. Especially on the rough, cracked patches. Just give yourself 30 minutes in between coats.
Mink oil and other animal fat creams will darken leather.