I'm ready to buy some sunglasses for lawnmowing, driving, and general use. I figure it will take two, maybe three different pairs to cover all the bases. I'm looking chiefly at the three brands sold here: American Optical, Randolph Engineering, and Serengeti by Corning. I favor glass for its clarity, and the Randolphs in particular look sufficiently shatter resistant. Which sunglass features are best for cutting grass? polarized or non-polarized? glass or plastic? neutral gray or "detail enhancing" brown for quickly seeing sticks and quickly distinguishing cut grass from uncut? photochromatic or nonchanging? hooked temples (so the glasses don't slip down your nose when you sweat)? What else? Do you see sunglasses as an investment or an expense that's good for maybe one season?