I've still got a few big Halon-charged units whose
gauges say they're fine,
but I know that Halon's a no-no because it eats a hole in the sky. So
All I can say to that is that you should compare the environmental damage
done by a couple of Halon fire extinguishers with the damage that would
be done if you had to rebuild all your classic computers and other stuff
from scratch.
-tony