"Robert11" wrote in message

c. What's a good rule of thumb regarding how often to request the gas
company to re-calibrate them ? Do they have to honor your request (by
Law) ?

I don' know about all states, but we have gas at work. We got a notice
that the meter would be replaced as required by law after 10 years. This is
an industrial meter but check local regulations. Chances are, you utility
has a web page with all the information you need.
--
Ed
http://pages.cthome.net/edhome/