In my opinion, one of the best things you can do is a quick and simple wipe down of a frequently used leather upholstery piece with a damp cloth that has a very small amount of cleaner on it. And I'm talking every two weeks. This is not a big production like getting out the leather care kits, its simply a hit and run. This will virtually stop leather discoloring or dirt build up.. Think of your kitchen counter and what it would be like if you didn't wipe it down but every 6 months....gross, right? Or some jeans you wore 6 days in a row without washing....the leather will accumulate dirt and body oils from hands and head. Do that 15 second wipe down on the tops of the arms and the headrest, AND if you have a leather steering wheel in your car or truck, get that too, because it will be nasty.
At my home here's what I do. I make my own juice and keep it in a spritzer bottle from Amazon. And some of the Microfiber towels that you can buy at Costco or Amazon, Target, etc.
* Fill it 90% with tap water.
* Add 2 oz of White Vinegar
* Add 1 pump liquid hand soap. (not dishwashing, too harsh). Do not use two pumps, too much soap is not good.
Shake it and now you have one of the best cleaners around all for about 25 cents of content. Spray it on your Microfiber towel (Not directly on the leather) and do that quick wipe down. That's it! Your leather will stay clean