I wipe the leather down with a soft MF towel, lightly dampened with distilled water, every couple weeks. I lightly condition the leather with Zaino conditioner every month to two months. I use the Zaino cleaner on the leather every four-six months.
Keeping the leather conditioned is important. As to the conditioner, TraderAlex1 on Edmunds.com says that the auto leather makers ("tanners") have tested all the national brands, extensively, and have found them all to be basically OK. He suggests to use what you like.
An idea has been circulating that you should not use products containing oils on modern auto leathers. All modern auto leathers have a "top coat" applied by the tanners per the auto maker's specifications. The top coat is designed to accomplish various purposes, protect the leather, etc. The idea is that products containing oils will break down the top coat.
TraderAlex1 posts on Edmunds.com. He is a dealer is hides. I asked him about this. TradeAlex1 wrote a long piece in response, politely refuting the idea.
http://townhall-talk2.edmunds.com/[email protected]^[email protected]/450 He has pointed out that 1. hides come from animals and they naturally have oils and fats in them (fats, which exist in hides, are simply oils that are solid at room temperature) 2. products containing oil -- which many national brands do -- have been tested by the tanners and they are OK. In fact, one of the big three tanners, Eagle Ottawa, sells a product, Tanners Preserve, that has oil.
Be aware, however, that certain oils, particularly straight oils like mink oil or neatsfoot oils, can perminantly darken the leather, and not always in a consistent manner. So, although I use mink oil on leather goods I make (as a hobby) those leathers are vegetable dyed and they are black to begin with. I would never use straight mink oil on light leather or modern auto leather, particularly if it was a light color leather. I guess you could use it on black, but, man, you'd have to let it sit awhile -- maybe a few days -- to let it soak in throughly. I'd go with a blended product, a leather conditioner.
TraderAlex1 says that while it is not horrible to use a combination cleaner/conditioner, it is better to use seperate products.
A big enemy of the leather is light, particularly UV, which is one reason why 303 protectant is popular on this site. Keeping your car garaged and covered when it is out of a garage is one of the best things you can do for the leather (and the car). This is also a reason to tint the windows (to cut down on the light and UV).
Lastly, NEVER use saddle soap on modern auto leather. Saddle soap does work on saddle leather, which is vegetable tanned. Most modern leather is chrome tanned and saddle soap does not work well with it. Use a leather cleaner.