For most rain jackets, new waterproof coatings can be reapplied for years, saving you money by prolonging the product's life. However, everything wears out eventually. Once the interior lining of a rain jacket begins to peel away or flake, it is time to start looking for a new one. If it is only doing this in small areas, you might have some life left, but you may not want to wear it in heavy rain.