Dish towels should be washed regularly, ideally every few days or more frequently if they become heavily soiled. Regular washing helps prevent the buildup of bacteria and germs on the towel, maintaining a hygienic kitchen environment. If a dish towel is used for specific tasks like wiping up spills or handling raw meat, it's advisable to wash it after each use to avoid cross-contamination. Always follow the care instructions on the towel label for the best washing practices.