Monthly service does not apply in the plumbing and heating business. On average, our clients call us every 2 plus years. We recommend annual inspections of the plumbing and heating systems with a preventative maintenance mind set. We also send mailings twice a year with helpful tips. The idea is to keep us top of mind for clients WHEN they need our services. Most of our clients call us again and again over years with very low pressure sales tactics. Things break, people call us, we answer the phone 24/7 and get a technician to solve the problem to their door. I guess you call that customer service!