Buy a smaller size, if that's really all you need - even though it might be a little more expensive. Make a list before going to the store, so you won't buy stuff you already have. Don't take two rolls, because today's special is cassoulet, which is a heavy meal, and the second roll didn't want to end up in the trash with a couple of leftover lettuce leaves.
I can't seem to find it now, but I remember reading about a restaurant in Paris which serves food made from what most people would consider garbage - peelings from vegetables, etc.
Well, I've found the thread on food wastage - obviously far more is discarded by industry, but I still hate throwing out food. Sometimes I'm just not hungry. I do use scraps of vegetables in soup stock, which I make often.