The optimal age to spay or neuter a cat is before it reaches 5 months of age. For owned cats, the optimal age would be 4 to 5 months, while for cats in shelters, the optimal age is before 5 months of age. However, there is some debate among veterinarians about the best time to spay or neuter a cat. Some recommend early or pediatric spay/neuter, which is done at six to eight weeks of age, while others recommend standard spay/neuter, which is done at five to six months of age. Waiting until after the first heat, somewhere between eight to twelve months of age, is another option. However, it is important to note that cats can begin reproducing as young as 4 to 6 months of age, so it is best to have them spayed or neutered before they reach puberty or have their first heat cycle to prevent accidental pregnancy or certain health conditions. Ultimately, the decision to spay or neuter a cat should be made in consultation with a veterinarian, who can advise on the best time based on the cats individual health and circumstances.