Leather is dead skin. It's organic. It dries out, cracks, and loses its structure over time, the same way every other organic thing does. Conditioning replenishes the natural oils that the leather lost to weather, sweat, salt, and just sitting around.
How often. If you wear the boot outside daily — every four to six weeks. If you wear it indoors mostly, dry environments — every two to three months. If the boot got soaked, condition it after it dries fully. If you can see the leather looking gray-pale instead of its normal color, you're already overdue.
What to use. Three categories work fine for work boots. Mink oil is heavy, water-resistant, and darkens the leather noticeably — best for outdoor boots that need waterproofing. Obenauf's LP is a heavy beeswax-based product, very durable, also darkens. Leather-specific conditioner from Red Wing, Bickmore Bick 4, or Lexol — lighter, less darkening, good for boots you don't want to change color much.
What not to use. Mink oil on a fashion boot you bought because the leather was a specific shade — it'll come out two shades darker. Saddle soap as a conditioner — saddle soap is a cleaner, not a conditioner. Use the soap first, condition second. Vegetable oil, mineral oil, motor oil — all of these are bad ideas, and yes, people try.
How to do it. Brush the dirt off first with a soft brush. Wipe the boot down with a damp cloth. Let it dry to slightly damp, not wet. Apply the conditioner with a clean cloth or your fingers in small circles, getting into the seams and the welt. Less is more — too much oil sits on the surface and attracts dirt. Let it sit overnight. Wipe off any excess in the morning.
Don't condition new boots right out of the box. The factory finish is already protected. Wear them for a month or two first, let your foot break the leather in, then condition. Conditioning a brand-new boot can over-soften the structure and the heel will collapse early.
We sell most of the major conditioners in the front of the shop. If you bought the boots from us, the conditioner is half the price of the boot's first repair. Cheap insurance.