It is fine to "keep going on" about your thoughts. Saying goodbye to a pet friend is one of the hardest things imaginable. If he is getting up and is alert, enjoy the time you still have.

The things that will tip you off that the time has come will be things like refusing to eat or drink, uncontrollable bowels, severe pain that absorbs his attention. You will know yourself; don't let anyone rush you into it. Your vet can advise you, but only you know Rufus well enough to know for sure when it is time.

I wish I had know about Pet Talk when we lost our other dog. It would have really helped me to be able to talk about it then.