That's good! Many people don't walk their dogs at all! A rule of thumb is to walk your dog at least 1/4 of a mile for every 10 pounds of body weight each day.
According to Dr. A. Luescher, board-certified veterinary behaviorist, formerly of Purdue University, one of the most important things you can do for your dog's mental health is to take him/her on a minimum of a once daily walk OFF the property.
I walk my own dogs less than I let them run off leash in areas where I can do this away from other people and dogs - out in the country. But my dogs both have excellent recall. I do not recommend this unless your dog has excellent recall and I do not recommend doing it in town.