Owners of pets with chronic or terminal illnesses commonly ask veterinary professionals - how will I know when it's time? Meaning, how will they know when it is time to consider humane euthanasia to end a pet's suffering? Most professionals are proficient in guiding and advising their clients, however recommendations are typically based on their personal knowledge and individual experiences. Their recommendations take into account objective information such as lab test results or findings seen on imaging (e.g. x-rays or ultrasound). However, there is a potential for a mismatch in a professional's subjective assessment of a pet's quality of life and that of its owner. Although a variety of questionnaires and survey instruments have been developed to assist clinicians in assessing patients with various problems (pain, skin disease, diabetes mellitus, etc.) a validated quality of life indicator instrument for dogs with cancer has not been previously known to veterinary professionals. In this Specialty Update we discuss a recent publication that reported on the components of a newly developed and validated quality of life instrument for use in dogs with cancer. It is a simple and practical questionnaire that includes 17 points for consideration when assessing quality of life. Although this instrument was developed for use in dogs with cancer, this important information can be helpful for guiding individuals when assessing the quality of life of dogs and cats with chronic or terminal illnesses. Running time: 16 mins Free registration for Premium Membership subscribers http://vetvine.com/article/181/evidence-based-update-subscriptions). Basic Member Fee: $14.95