Fertilizing and mowing your yard, clear to the end of the season, is a good down payment for a healthy yard the next year. A yard that has been fertilized in the fall will have nitrogen in reserve for the spring, and green up as soon as the soil temperature get's above 55 degrees.
Mowing the grass as late as possible, and chopping up the leaves, will keep the grass clear of debris, and short through winter. If the grass is short enough, it won't fold over and lay down, which allows air get down to the soil.