. I really do not see anything that you should be concerned about. It really does nothing but protect the boot (both water, and wear), and darken it a little. If you have the Amber Harness color, then you can notice that the leather has a slightly greasy/moist look and feel to it. Obenauf's would just add to this effect. You are simply treating the leather, not applying a polish. Treating the leather is something that you will want to do anyways, if you want your boots to last for as long as possible. Not to say the boots won't last without it. Conditioning them is just like applying moisturizer and sunblock to your skin to protect it from daily wear and tear, and harsh UV rays. You and your boots will look better in the years to come than those who failed to take precautions... blah blah blah . . Kk thanks! .