How should I condition leather before storing it in a dry climate?

Clean the leather with a dedicated cleaner (no alcohol or harsh chemicals), then apply a conditioner for finished leather—like Bickmore or Leather Honey. Let it soak in for a few hours, buff gently, stuff with acid-free tissue paper, wrap in a dust bag or cotton pillowcase, and store in stable humidity. In very dry climates like Phoenix, keep relative humidity above 30% with a small humidifier or damp sponge. Do this twice a year.