There is no way I used 200 gallons before the light comes on I think it’s a time issue of not using it daily.
The cost of replacement is a financial decision I think you should make a filter that you could open and replace the filter it’s self I know it cost to build the filter/housing as a unit but then again some idiot would screw it up and flood the inside of the unit and sue you for damages because they did not install it correctly.