I have several a G19+G23, Sig P239+Sig P226, S&W 638+Ruger GP100.
Ditto here. I usually have triples of my carry guns. In the case of triples, the third one is a safe queen which will go into the rotation if either the carry gun or the range gun is down or out.I have doubles (or triples) of all my carry guns.
I'm not so worried about it getting taken in a good shoot as I am having it go down for repairs / theft / etc.
In a pair, one will be carry and the other will be for the range. So that way if something wears out, it happens at the range and not when I need it most.