I need a holster for my model 37. I am not sure if the polymer holsters will wear off the bluing, so I am thinking about a leather holster, inside the waist band model.
The holster material is not what wears on the finish. The grit and dirt that comes off the fired gun and embeds itself inside the holster is what does that. After it builds up it is just like fine valve lapping compound. Keeping the holster clean will reduce finish wear but will not completely eliminate it. Kydex should be easier to clean and dry than leather. Leather will require a lot more work to clean and dry. If you want the finish to hold up over the years don't ever put it in a holster. On a gun that I plan to carry 24/7 I don't worry about the finish. It can be refinished. I suppose you have to decide if this is a working gun or a safe queen.