Hello; I have a tank in my basemennt from back in the late 1950's or the early 1960's. It was one of those with an angle iron frame and a slate bottom. The iron frame was painted black with white streaks on it. I believe it was my second tank. The iron frame rusted away decades ago and the advent of silicone saved the tank. One end of the tank is cracked and patched with a glass panel. It is scratched and ugly and I am not sure if it still holds water.
I was 12 or 13 when I earned enough money to upgrade from a 5 gallon to the 20 gallon long. I am 67 now. I will do fine if I get rid of the tank and may keep it around a bit longer as long as I have a spot for it.
Old tanks that do not leak are worth keeping around.