“A man with a watch knows what time it is. A man with two watches is never sure.”
I would also say that a man with a voltmeter knows what voltage it is. A man with two voltmeters is never sure.
Between the Solartron 7150, the HP 3456A and the HP 3457A I have three voltmeters… which satisfies Segal’s law.
At least the HP3456A and the HP 3457A read the same and so all is well with the world.