Paint has three components: the binder, the pigment and the liquid. The best paints contain a higher volume of solid materials. Pay close attention to the solid content. For example, a $13 gallon of paint with a solid content of 19 percent might cover about 200 square feet, while a $20 gallon of paint with 41 percent solid content will cover about twice that amount. The binder is the most important factor in the durability. Some paints also have additives to enhance their performance, such as mildewcide.