Mostly staining of leather with body oils is caused be medication a person is taking. Sometimes it can be quite dramatic. Keep the Protector coating on the leather out of the kit and stay on top of it as that is your best chance to barrier the hide. Yes, you can get seat or back cushion casings a la carte. In a Gr 2 leather, a new seat casing is $ 260 + shipping, a back casing is done on a quote basis. Its identical to the original casing in all aspects.