When outfitting or guiding I always had at least one extra rifle in camp. For myself, I don't because I have reliable rifles (for the most part.)
The ones that could be less then perfectly reliable (like my flintlocks) which could fail from time to time (so far it's never happend to me, but it could) are used anyway because that's part of the fun of using an old fashioned gun. But for my centerfire rifles I would have to say the one that is likely the least reliable potentially is my Mossberg MVP because it has the smallest and weakest extractor. However I have never had to replace it yet. So far it's been 100% flawless. As a gunsmith I fix broken guns all the time, but I have been blessed and in all my years of hunting I have never broken a gun. I have broken 2 scopes, but both times I had iron sights too, so I removed the scopes and continued to hunt.
My lever actions have simple spring hook extractors but I have never had a problem with any of the ever. I have had to replace extractors in many other guns in 50+ years of gunsmithing, but is a rifle is kept relatively clean and oiled, failure is not all that common. Horse wrecks and 4 Wheeler wrecks cause a large share of broken stocks. I NEVER leave my rifle on a horse when I get off and I don't take 4 wheelers into places that are so steep that rolling or flipping one is likely.
So for my own hunting I do not take 2 or more rifle because of any fear of a failure . When I was a Marine I only carried one, and I can't think of ANY situation where having a rifle fail would be worse than "Indian Country", but I still carried only one. The idea that my rifle is so prone to fail I may need to seems like never wanting to go outside because of Covid10, fearing lightening because of a few drifting clouds or worrying about rattle snakes under every rock.
The odds are Waaaaaaaaaaaaaaaaaaaaaaaaaaaay in my favor that I will do fine with 1 good rifle.
Now I do take a few guns on some hunts when I want to try different bullets and those bullets are zeroed in those different guns, but that's NOT because I think I will need a spare.
