4 foot T12 fluorescent bulbs (Melrose)

Our fluorescent fixture went bad, so have replaced it with an LED one. I have 2, 4 foot older type T12 fluorescent bulbs available. One has been used for some time, but I never noticed any dimming or flickering, so may have life left, but I have no way to test it. Other bulb never used from its 2-pack. Porch pickup in Melrose.