The decision when to euthanize is as individual and personal as you and your pet are. This is a judgment that only you can make, and it involves great personal courage and sacrifice. Many people fear they will not be able to recognize when the time is right. Do not hesitate to seek guidance from your veterinarian. It is good to include family members or friends who share a close bond with your pet in the decision-making process. This is a time when you will need the support of those who truly understand. Also, the Association of Pet Loss and Bereavement has five online chatrooms that a pet owner can attend, and receive exceptional supervised peer support.
Some important things to take into consideration, contemplating this decision may be:
Does the pet still seem to enjoy life? Is he/she able to carry out normal body functions as before — eating, walking, and eliminating? Is the pet in pain? What is the medical prognosis? What are the treatment options? Will they create an uncomfortable quality of life?
Another important consideration is, are you able to afford the cost of treatment? For some, this must be the overriding determiner. Regardless of their opinions, other people should not stand in judgment of this. Regardless of their opinions, other people should not stand in judgment of this. In making the final decision it may be helpful to weigh the good days versus the bad days. When the bad override the good, it probably is the right time.
Remember, no one knows your pet better than you do. You have spent a great deal of time learning to communicate with him/her by reading the body language. Attend to what your pet may be trying to communicate. And trust what your heart tells you. Later, you may question this, but that is a natural reaction, and you should rely on your present reasoning.
~ taken from the Association of Pet Loss and Bereavement