The life expectancy of a gas heater can vary depending on a number of factors, including the type of gas heater, the quality of the heater, and how well it is maintained. In general, however, gas heaters can last for a long time. For example, a gas furnace has an average life expectancy of 15-20 years, while a gas boiler can last for up to 25 years or more. It’s important to note that the life expectancy of a gas heater can be extended with regular maintenance and by replacing any worn or damaged parts. To ensure that your gas heater lasts as long as possible, it’s a good idea to have it serviced by a professional on a regular basis.