Art, I don't think it matters what others think about a closing session (I only had one and it was not helpful at all, but I didn't have the number of years into it that you did). I do think, based on everything you've posted, that you can't rest without a closing session, so why not just plan on that?

Also, you can make this look like however you want it to look: a closing session with the door left open for occasional check ins; a final closure with no open door; or something else.

I wish I could have options, but my therapist is going to retire and move away. She said we can continue long distance for a few years beyond that, but who knows if that will work out. If I had my way, I would not end at all. I don't see a problem with therapy being any way a person wants it to be, if it's helpful.