The answer to 'how often to replace evaporator coil' is that the evaporator coil in your HVAC system should typically be replaced every 10-15 years, or when it becomes damaged or worn out. The evaporator coil is a critical component that absorbs heat from the air in your home, and over time it can become corroded, clogged, or damaged, reducing its efficiency and cooling capacity.
Regular maintenance and cleaning of the evaporator coil can help extend its lifespan, but eventually, it will need to be replaced. Factors like the age of your HVAC system, the climate in your area, and how often the system is used can all impact the lifespan of the evaporator coil. It's a good idea to have a professional HVAC technician inspect your system regularly and advise you on when the evaporator coil may need to be replaced.