We highly recommend the annual service of your heating system. The ideal time to schedule for this maintenance is between April and October. We cannot guarantee a tune up schedule during the winter months. Customers who maintain an annual service have far less service needed during the heating season. The Tune up includes replacement of the Filter, Nozzle and Strainer. The unit will be thoroughly vacuumed up to the chimney base. An efficiency test will be completed. I am confident you will know the people coming in to your home are honest, dependable and professional. They also carry Dog Biscuits at all times!