It's probably the sulphuric acid in the air and esp. in the rain water that is causing your shoes to crack prematurely. Large cities with lots of automobiles are notorious. As for neatsfoot--it's great on saddles but not so much on saddleshoes. Too oily and too heavy. Lexol NF is supposedly a pure neatsfoot that has been homogenized but it will still stain light coloured leather.