Hi,
If cleaning with saddle soap or anything involving water, try to keep the leather as dry as possible. I have a knife set--two knives, one sheath--that was made in pre-war Germany I was given about 1961-62. The sheath was original, in pretty good shape, and those knives went with me on backpacking, fishing and bird hunting trips until about the early '90s. Last trip out, the leather got soaked, and the sheath died. That old dry leather needs a lot of "nourishment" to be able to take as much moisture as newer stuff will...
I once posed a question about leather care products to one of our resident leather workers, Viking Queen. Cathy introduced me to a product called "Montana Pitch Blend" which she told me is quite popular amongs leather workers. It doesn't contain petroleum products, as many current offerings do. I couldn't find it locally, but did find "Huberd's Shoe Grease" which is probably the product the Montana brand folks are competing with most directly. It's a beeswax and pine pitch mix, doesn't discolor leather very much at all, and has been around since 1929, so I figure it must be ok. It's done a nice job for me on some other old leather. If you don't mind ordering online, both products are readily available.
Rick C