We bought extra filters for the Berkey. I forget how many thousands of gallons could be processed. But @ a gallon per day for each of us, we would still have spare unused filters when we are both 6 feet under.
I think a weakness in our system would be in case of earth quakes. We probably need to put something on each shelf to keep stuff from jiggling off the shelves.
I did that more because I am likely to klutz something off the side of the shelf.
I had mr. mm cut some pieces of plywood and I painted them and wedged them in the sides.
The front was not covered but we don't get earthquakes.