Originally Posted by fritzl
well, there's no consensus on this. one method is to use a special oil for that. this treatment is recommended e.g. twice a year. northhampton novice is the real expert on these kind of things.
No expert, but no longer a novice either!
Fritzl is right, there is no genuine consensus on this.
But several products do exist to 'care for' your leather soles. I would only suggest you consider this range of products if 1) You are really hard on your leather soles, and/or 2) You regularly walk in the rain or 3) You own shoes which have leather soles which are known to have a propensity to wear down relatively quickly (e.g. I include C&J Benchgrade in this category and some Lobbs).
Leather sole oil is the most common, it should not be used on new or newish soles and should not be used on cemented soles. It claims to make your soles last longer, in my limited experience it did work. I've heard similar results can be achieved by working v.small amounts of neutral wax into the soles - I've never tried this but just remember to buff properly and not to do this on new/newish soles!