Good stuff above,(Lexol), but there as an alternative not listed, Tanner leather care products.
Tanners Preserve Leather Cleaner & Leather Conditioner are recommended by Eagle Ottawa, the leading supplier to the U.S. auto industry. Eagle Ottawa has been making leather since 1865, so they know how to take care of it. They evaluated and tested both of these products in their laboratories during development to ensure best performance for their validation. Eagle Ottawa supplies most of the leather interiors for numerous OEM including Chrysler, BMW, Mercedes, BMW, Land Rover, etc. etc.