OP here. Thank you for the responses. DH, DD, and I read through them all, discussed what would be best for our dog, and decided it is time. l made the appointment for Monday morning. Now that the decision is made, we feel immense relief. We will spend this weekend spoiling our old dog rotten with everything she loves. She deserves it.

Two of our kitties have crossed that bridge this year.

They were very attached to each other. The male was older by a few years. The female thought the sun rose and set on the male. The male had been going downhill, and then his old kitty body began breaking down in earnest. We steeled ourselves and had him put down. The female had advanced cancer, but she'd been holding up well with palliative care. She went downhill fast after he left us. We made the hard decision.

One thing that comforts me is knowing we did our best to give them a good life. We always tried to do right by them. Putting them down when it was time was hard on us, but the only kind choice for them.