What is the life span of an electricity meter?

Today an old system meter that boasts a 75+ year life is simply not valid anymore.

As we move forward in the information age the old meters Are being phased out for incompatibility reasons and none will be in you (In America) in the next 12 years.
In addition the mechanical life is relative and depends on a multitude of reasons; therefore you can boast 75+ years but you can not promise it. A meters life is subject to the volatility of power than can and often does ruin your meter system.....

So I would tell you an average of 12 years with exponent.