As you deck your halls with boughs of holly, don't forget to adorn your smoke detectors with fresh batteries. And if you've disconnected the one that's always been just a tad too close to the stove and acts more like a dinner bell than a smoke detector, it would be smart to invest in a new one and install it in that general vicinity. With so many people becoming quasi-electricians at this time of year... stringing lights together in seemingly endless miles of cords... and dangling pine boughs in somewhat dangerous locations because their inherent beauty supersedes the lack of safety precautions... it's really a great idea to make sure you do your best not to overload circuits and to have your smoke detectors in working order.
Ask at your local fire hall and see if they have smoke detectors available to the public. Make a deal with a local hardware store to give them to your clients at a discount. Or maybe you want to offer some batteries for Christmas to your clients. Send them a Christmas greeting with a certificate that they can redeem for a 9-volt battery. It'll give you a great excuse to stop by and you'll be spreading news to them that you care.