I carry a slow to reload gun that contains only 5 shots, a Smith & Wesson J frame, so yes, I carry a backup, another Smith J frame and sometimes three.
Any time trouble has come my way it was at least two guys and often it is three to four guys and sometimes more. Guys who are looking to do harmful things operate in wolf packs, so having a gun with only 5 shots doesn't sound wise unless you have a backup.
Should I carry a gun with a larger capacity? Well I like the way the J frames just drop into a pocket, no harnesses, no belts, no rigs, no holsters (depending on the pocket), just grab the gun and go. There are plenty of other reasons I like the J frames over a larger higher capacity gun.
It's best to view the J frame as one half or one third of a gun, this way it doesn't sound so odd that a person would carry two and possibly three J frames, and at 11 ounces or 13 ounces for the scandium J frames, they weigh next to nothing.
I also carry pepper spray as a less than lethal option for problems where pepper spray would suffice and it has come in handy on more than one occasion. For what it's worth, though I didn't intend to buy this brand, it worked out that I have Smith & Wesson brand pepper spray.