Preventing the formation of cavities and tooth decay is one of the most important health benefits of flossing teeth. So, besides brushing, flossing too is essential for proper cleaning of teeth. If you could spend 2 minutes per day doing something that would help you live longer, would you do it? Flossing once a day increases your life expectancy by 6 years. Flossing prevents -Bad breath, Formation of cavities, Tartar buildup, Gum diseases.