Forgive me for being brief, this is a subject I prefer to avoid but a long time friend may be taking a final journey in a few days. We've enjoyed his company every time he comes to visit. We've lost a lot of long time friends of the last year or so. Puppies I met when I first started working after college 13 years ago are now old dogs. Where has the time gone?
So when is it time to let go? It's a question we love and hate to hear. We love that you care enough about your pet to ask us this question. Usually this question means that we'll be loosing a long time doggy or kitty friend (yes we consider you and your pets our friends; at least the ones that don't bite).
There is usually a reason for asking. Your pet has gotten old and is slowing down.
The answer requires some explanation. But first, most veterinary clinics require a medical reason; not that you just don't want them anymore or are being vengeful against someone you once loved.
We have three guidelines: They don't enjoy your company / seek your attention, they are no longer interested in eating, are wasting away and prefer to be alone.
I've added another: if they can't see well, can't hold their urine, are arthritic and bit at the hands that care for them. This is the example of our friend. His family has grandchildren and they are concerned about them.
Yes, you will miss them, you will feel the pain of their loss, and you will experience grief. It can't be helped but given time it will get better. There will be other pets to share your love and life with and there will be people who understand and will share hugs and tears with and we will have a box of tissue ready.