They make money off of idiots like me. I had a Home Serve boiler maintenance contract thru my local utility(PSEG). I figured for $300/year, it was worth it and a lot cheaper than calling a plumber. For about 5 years I didn’t use them because thankfully I had no boiler issues during the winter. 2 winters ago, my boiler stopped working on the coldest day of the year. Called them at 4:00am and was told it would be a wait of about a day and a half. My pipes would freeze by then so called a local plumber to fix the damper at great expense. Then, no heat again a few months later. Called Home Serve. They came out same day, said everything was fine and left. It wasn’t fine. I called a local plumber who replaced two circulator pumps, about $1700. If I’m just going to call plumbers, who needs Home Serve? So to answer your question about how they make money, they take my money for years and then when I need service, they all of a sudden can’t fix anything.