I use plastic bags usually, but I do reuse them. See, I have cats and hamsters, and well, if you take their used litter out and dump it directly into the trash, it will stink to high heavens. So, I put it on a plastic bag (that I save in a bag-holder), tie it up, and then throw it in the trash. I also use palstic bags to wrap potentially leakable items when I travel. But, for carrying things around, I use canvas bags, and use them for shopping as well when I don't need plastic bags.