Although cats have a reputation for being relatively independent, domestic cats require love and attention from their owners. A balanced daily diet, such as that provided by high-quality commercial cat food, is essential for health and longevity, as is a regular supply of fresh water. Regular cleaning of litter pans is necessary to prevent disease; some cats will refuse to use a badly soiled litter pan. Cats' claws should be trimmed frequently. To prevent damage to furniture, cats that live indoors should be provided with a scratching post, preferably covered with a rough material such as sisal rope. Cats use their tongues to clean their coats, and they normally swallow any loose hair. All cats, including shorthairs, should be brushed weekly to remove loose hair; this will help prevent hairballs from forming in their stomachs. A few longhaired breeds, such as the Persian and the Himalayan, require daily combing to prevent their long, soft fur from matting.