How do I know when it is best to euthanize or "put down" my cat?

How do I know when it is best to euthanize or "put down" my cat?

Bernadine D. Cruz. DVM (Companion Animal Medicine Expert, Laguna Hills Animal Hospital ) gives expert video advice on: How can I keep my cat comfortable when she gets old?; How can I prepare my kids and myself emotionally before putting our cat down?; How long should I wait to get a new cat after my cat's death? and more...