For the most part, all you really need is a good horsehair brush. This is enough to clean off any surface dirt/dust. For cleaning beyond that, you can use saddle soap. The less aggressive the better, because it will begin to strip away the oils and waxes you want in the leather so be cautious.

If you find that the leather is drying out or beginning to crack you can apply some conditioner. Generally conditioner is just oil and wax. Oil will quench a thirsty leather and wax will provide some weatherproofing. If it has more ingredients proceed with caution. Also keep in mind that oil will darken most leather so it's a good idea to test in an inconspicuous area before going to town. Be sure to clean thoroughly before conditioning as the wax can seal in any dirt present on the item.

Fact: Leather will mark and scratch. It's natural to want to keep your leather piece as close to perfect for as long as you possibly can, especially if you spent a lot of money on it. Remember that the beautiful thing about leather is every one of those marks will blend in over time and add to the uniqueness of how you lived with it, which is to be celebrated!