Neutering reduces aggression towards other animals and decreases the likelihood of fight-related injuries. Neutering lessens other behavior problems like fence jumping, which are brought on by the desire to find a mate. Neutering greatly increases longevity. Altered males are less likely to get hit by cars during quests for females. They also will not develop prostate problems or testicular tumors.
Neutering decreases embarrassing behavior traits like leg-mounting.
It helps prevent cats from spraying their homes with foul-smelling urine. And when you neuter a cat, those ear-splitting serenades for the benefit of potential mates are a thing of the past.