Even if you are happily employed, you should keep your network up-to-date
. You never know if or when you will need to get in touch with a particular person. Keep in touch with such simple gestures as an e-mail, birthday wish or holiday card. When possible, offer what you can from your area of expertise to them. By helping them, they will be more apt to help you if the need arises, plus it is the courteous thing to do. Happy job search networking!