It seems like you can never have one pair of glasses that handles every situation. With a pair of frames with interchangeable lenses you can have one pair of glasses with many uses. Sometimes you are up on Mt. Baker when the light is low and a nice set of lenses to see in the snow or when you are in Bali and the sun shines with such an intensity you will need to have a darker set of lenses. You can get a set manufactured by Marmot, Oakley, Smith, or Switch Sunglasses in grey, yellow, black, red, green, amber, or silver. Really there is something for every situation.