Customers water heater is beginning to fail and needs to be replaced. Attempted to remove existing water heater but cabinet opening was 3 inches to small to get water heater out. Explained to customer I’d have to remive face of cabinet and associated trim in order to get the water heater out and install the new water heater. After gaining proper access I was able to install new water heater. Explained to customer I strongly recommended retrofitting cabinet opening in order to make large to easily remove and work on water heater in the future.