I am a huge fan of cooking once and eating twice....or more. I live alone and always found cooking for 1 to be a waste of energy. In the past I would go for quick, processed, frozen meals and take-out over cooking. This is not only unhealthy but very costly as well!
In the last year I have made a huge effort to cook more. One of my favorite recipes is Black-Bean Quinoa Salad which is easy to make and freezes well. Anytime I cook chicken or fish I cut the piece in 1/2 and bring the other 1/2 for lunch the next day. With grains such as couscous, quinoa or brown rice I will make 2 or more servings so that I have them around during the week. I also keep regular and frozen veggies in the house at all times. With all this extra food there is no excuse for not throwing together something yummy for lunch & dinner.
I also like to freeze baked goods. As much as I love to bake, I also love to eat! This is dangerous. To make sure I don't scarf down an entire loaf of pumpkin bread or a dozen muffins I freeze what I bake. After it's cooled I cut the bread into slices and wrap in foil or wax paper. For muffins I just put them in a large Tupperware container. When I feel the need for bread or a muffin I just grab it from the freezer. Since these are homemade they are much healthier than what I would find at my local deli or bakery.
Whether you cook for yourself or for your family cooking extra is the way to go. Leftovers will not only save you time but will save you calories and $ as well.