Using less plastic bags means less “stuff” around the house, which means less unnecessary littering of the environment.  Bringing your own durable bag to use over and over again is the biggest bang for your buck.  It doesn’t have to be a fancy and decorated tote bag — an empty backpack works just as fine.  It’s easy to forget in the course of the day to bring your own bag if you’re going to do groceries after work or classes, so keep one tucked away in your briefcase, handbag, or backpack.  It’s a small thing to do, but you’ll feel much better about it when you’re in line at the grocery store and you know that you have your own bag!  (But if you do find yourself with plastic bags — whether from grocery or window shopping — they can also be used as trash bags)