There are a lot of good comments on here. For holsters we advise the good ol shoe polish for touch up and a little saddle soap on a damp not wet rag.
Be extremely careful with rubbing alcohol this can screw up the finish and color that on many leather goods
There are many types of leather tanning processes out there and each has a purpose with different care needs, saddles need more oil to penetrate the depth of the leather and keep them soft and usable where holsters need to maintain their stiffness to securely hold the weapon but boots can have mink oil (silicone base) to help waterproof them but never use mink oil on saddle tack as it will cause dry rot . In short different leather goods require different care needs.
Some oils are good but too much will damage goods