After trying more than a dozen leather creams, conditioners and polishes, I've found what I think is the best option. Collonil 1909 Creme de Luxe (made in Germany) nourishes and revives leather that has become dry. It does not leave an oily feeling on the leather, nor does it cause the leather to darken like other leather conditioners do.
Sold in 100ml jars.
Comes with a soft applicator / buffing cloth.
Using the supplied cloth, wipe the leather clean up any dust or dirt before conditioning / polishing. Dip one corner of the cloth into the Creme de Luxe to transfer a small portion (the size of your fingernail) of the product to the cloth. Gently work the product into the leather and allow to dry for a few minutes. Use more product if needed. Then use the dry part of the cloth to buff the leather to a beautiful finish. Repeat this every few months or whenever the leather is feeling dry. Do not over condition or soak the leather - only a little is needed.