A 100% horsehair brush is a must have tool to maintain the luster and shine on your leather shoes and boots. Whether it is a shine brush or an applicator brush it will disperse the polish on the shoe and work the polish into the cracks and crevices to help waterproof the shoe. The shoe shine brush then takes off any excess polish and bring the leather up to a shine.
With both brushes you should have a black brush for only black shoes and neutral brushes for your browns and lighter colored shoes. Dark polish left on a brush will darken a lighter colored leather and is difficult to remove.
The brushes last a long time. Cleaning them with a soft cloth every so often to get off the old polish will help them last longer.