I don't think I voted but my answer would be 5....that said...
I've known a lot of people personally who have been in gunfights or "critical situations" where no shots were fired. I've also read a bunch of personal stories of people on the various websites and one "theme" keeps coming up. Those who carried "Mouse Guns", as in snubbes and below rarely ever carried them again as their primary unless there was no choice.
One of the ones I remember best was a retired LEO on the original Shooters.com. He lived somewhere in the mid west outside a fairly large city. He had always carried a SIG 9mm of some kind but one day he came on raving about his newly purchased Keltec .32 and how he was no longer carrying the 9mm.... Now while I have owned P32s since they came out and think they are the finest BOG/hideout gun ever made, I told him he was giving up an awful lot of firepower for "convenience"...he disagreed....
A few months go by and one Monday he posts that while he is still carrying the P32 in his pocket all the time, he has gone back to the 9mm while out and about.... Seem the previous morning he and his wife had to go to the big city very early...there was no traffic at all. They were in a industrial/warehouse type area when a pickup with three apparently hadn't been to bed yet drunks pulled up along side and started cat calls at his wife. They then began following them and finally tried running them off the road. He was able to escape the situation and once safe they pulled over shaking....it was then he realized if something had gone wrong the only thing between the 3-jerks and his wife was the little .32 in his pocket that he couldn't even access while seated....
But as I have written before, it isn't what you carry that keeps you out of the fight in the first place or prevail if it comes to it, but your knowledge, skills, attitude, training, tactics and awareness....but having "enough gun" helps.
Bob