New leather boots need something that'll penetrate at first. Lexol
http://www.lexol.com/lexol.html is what I recommend. Used it many years after a cleaning with glycerin saddle soap such as
http://www.outfitterssupply.com/Fiebing ... nfo/WLF109. Clean the leather with the soap, allow to dry, buff and polish, then add Lexol generously with a sponge, allow to soak in overnight and then apply neatsfoot oil or mink oil, or Hornady's Unique Case Lube (yes it's a great leather dressing).
Every day when I came home from felling trees, digging trenches, clearing trails or such, I'd soap my boots, let them dry, apply Lexol and then rest them the next day. Polish with wax before using again. Always alternated between two pair. Once every couple of weeks apply a coat of mink oil or such during winter. Main thing is clean any mud off as soon as possible, mud will suck the leather dry quicker than anything. I have several pairs of White's Smoke Jumper boots that date to 1986 that are still in service.
It also works on harness and saddles, ankle boots, bell boots, halters and anything made of leather.