There are many reasons to spay or neuter your pet. Here are just a few:
You are giving them a better chance at living a longer and healthier life.
In female dogs and cats, spaying can help prevent certain types of cancer, such as ovarian cancer, uterine cancer, and especially mammary cancer (breast cancer).
By spaying your female dog, you are eliminating her heat cycle, therefore you will not have to contend with unwanted restless male suitors, bloody discharge, and restlessness from your female dog.
In male dogs and cats, neutering can help prevent testicular cancer and unwanted behavior such as roaming, spraying, being territorial, aggression, and fighting, which can lead to the possible transfer of diseases.