The most important thing about leather is not what to do, but rather what
not to do. Never, never, never use any type of conditioner or other liquid care product that contains wax, or which doesn't list the ingredients on the bottle. Wax is a very common additive to leather care products because it produces a sheen that people like. However, liquified wax soaks into the pores of the leather, solidifies, and then causes the leather to dry out and crack. Once you've treated leather with a wax-containing product, you can never go back. You will have shortened the life of the leather permanently.
There are only two things I use on leather, and both are sold at HD dealers. The first is leather dressing, a thick clear grease. You only need this for leather that's subjected to a lot of water. It's also generally too messy for jackets unless you're putting them up for the summer. It will preserve leather almost indefinitely, and when you pull the jacket out again for winter use, it will look exactly like it did when you put it away. The second thing I use is Harley Davidson Leather Care. It's a white lotion that soaks in and disappears quickly. You can do a jacket in less than 10 minutes and it's ready to wear imediately. This is the only product I can always count on to be absolutely wax-free. At $4 per bottle, you can't go wrong.
FWIW, I have a heavy, thick leather jacket that I bought at a HD shop in NE PA back around 1991. It still looks brand new despite all these years of use and storage.
