I've been with my therapist more than four years.
Two years ago, I would have said I couldn't imagine ending. Every week was intense. I was gripped by the therapy process and working hard on changes in my relationships.
Two years later, I still go to therapy, but it is far less intense. I feel I have done all the work I can do in my relationships for now and my energy has moved to different things that do not require so much support. If something happened and I couldn't go anymore, I'd be OK. I would miss my therapist, but it would not gut me like it would have two years ago.
I wouldn't let insurance dictate things, but if you were already iffy on it anyway, you could just see how you feel about going much less.
I think therapy ends when the patient decides the patient wants to end. When the patient starts resenting the money and time spent on therapy and daydreams about how it could be better spent. When the patient feels no more personal progress is being made and it doesn't make sense to keep going when it's not producing much change. Stopping for awhile doesn't mean you're leaving therapy for ever and can never go back. Or that your process of growth and change has ended--it never will, hopefully.
I can imagine periods of time in the future when I'll really feel a *need* for therapy but now, at this point, I feel like if I wanted to "end" it I could. So I guess the question is, why am I not?

That would be a very good question and is one I ponder.