How many IUIs before IVF?

I am on my 4th <a href="https://glowing.com/glow-fertility-program">IUI</a> cycle, with a review call with my Dr tomorrow. I’m nervous. We have unexplained fertility. I am curious at how many <a href="https://glowing.com/glow-fertility-program">IUI</a> cycles your doctors recommend before moving onto <a href="https://glowing.com/glow-fertility-program">IVF</a>? I never saw myself in this position, and makes me sad the Dr might say it’s time for <a href="https://glowing.com/glow-fertility-program">IVF</a>.