My work carry and my lightest load outside of running is a j-frame, p-32, one speedloader and one speed strip. This is my level of comfort, and here is my reasons for carrying these items. I do not plan for the ordinary, but for the extordinary. I live a normal, sedate life, I work full time, go to school fulltime, and live in a nice neighborhood in northern virginia. That said, bad things do happen to good people in "nice" neighborhoods. I carry a backup gun, due to the things that can happen to your gun in a gunfight. It could be shot, or get dropped and thrown across the room, or it may be the first day ever it has failed to fire. Whatever the reason, I carry a second gun against that eventuality. Two, spare ammo and reloads. For autoloaders its a a no brainer, carry a second magazine, as magazine failure happens often and is real easy to fix IF you have a spare magazine. With revolvers, particullary j-frames I can see the logic of not carrying reloads. Reloads can be slow, the average gunfight only lasts...(insert whatever statistic you believe), if I shoot one attacker the rest will flee...all that is fine, and if you feel comfortable, well at least your carrying a gun. Im not trying to look down on those with that mindset, or say my way is better, but here is my opinion on carrying the extra ammo. Yes the reload is slower, but I can reload faster than not having a reload at all. The more I train, the faster I get at it too. Say the gunfight does last less than five rounds, and the other attackers have fled. What do you do on the way home, or while waiting for the police to arrive - you have anywhere from 0 to 4 shots left and thats it. What if the guys friends talk themselves into coming back, or the only reason they ran off was to get better weapons or more friends. I can find dozens of imagined or real world scenarios where extra ammo and spare guns could be handy, without getting exotic and coming up with farfetched scenarios. The hard part of finding scenarios where there was shooting and multiple attackers is there is not that many concealed carry shooting incidents, while tehre are many incidents of multiple attackers on regular people.
Me, I plan for the worst, hope for the best, and live my life out like normal. If I am ever attacked by a gang of street thugs, or one mugger, or the ninja mutant zombies of the world, I have prepared as much as i can for sucess. I plan to survive, and I continue to train with my chosen weapons while living my daily life. I do think its pretty silly to not at least have a speedstrip or two, but YMMV and its your life. Everyone needs to carry what they feel comfortable with and what works for me, certainly might not work for you.