Does neutered cats really live longer?

Hi, Does neutered cats really live longer? I have 2 indoor cats,both male, they're almost 3, and I was considering getting them neutered. Some say that it's not very good for the cat, there will be hormone imbalance situations. And some say that neutered pets live longer, because they don't fight that much and they're happier and so on. I just wonder if there is a scientific evidence backing up the living longer theory.(I really do hope they'll live longer so I can take care of them till they're old cats in their 20s. Just a fantasy of mine)  I'm still weighing the cons and pros about whether to get them neutered. Anyone have some good thoughts about this? Thank you.

If they have no behavioral or health problems and don't go outside, neutering will probably have no effect on their lifespan. For males, the main reason neutering would increase lifespan is because it would cut down on fighting, roaming, and spraying. Fighting spreads disease and of course causes injury and possible infection, roaming can get cats hit by cars, killed by cat-haters, and exposed to more cats to fight with, spraying can get cats put to sleep or thrown outside (where they'll roam and fight, exposing them to those dangers). I would recommend neutering but only to prevent future fighting between the 2 (even if they're friends, if a female in heat starts hanging around your house they could fight) or spraying (which can start at any time). It's better to do it when they're young and healthy so they heal easier and the anesthetic isn't much of a risk.

For females, the health benefits of spaying are much higher. Female cats are fairly prone to reproductive issues that shorten life expectancy.

I would get them neutered because if they ever sneak outside.... an unneutered cat will wander off in search of females. The sex drive is a powerful motivator and should they get outside you don't want them wondering off and getting lost.

As they age unneutered cats are more likely to spray in the house. I've had feral cats spray in my garage. The smell is difficult to remove.